An ac loss testing device and method for superconducting materials

Abstract

The application discloses an alternating current loss testing device and method for superconducting material, wherein the superconducting material comprises a base band buffer layer, a first superconducting layer and a second superconducting layer, the first superconducting layer and the second superconducting layer are located on opposite sides of the base band buffer layer, and the alternating current loss testing device for the superconducting material comprises a first current conducting strip, a second current conducting strip, a signal detection device and an alternating current power supply module; the first current conducting strip is electrically connected with a first end of the first superconducting layer, the second current conducting strip is electrically connected with a first end of the second superconducting layer, and a second end of the first superconducting layer is electrically connected with a second end of the second superconducting layer through a connecting conductive structure; the first current conducting strip receives an L-phase power supply signal of an alternating current power supply signal, and the second current conducting strip receives an N-phase power supply signal of the alternating current power supply signal; the signal detection device is configured to acquire a detection current and a detection voltage of the superconducting material, and acquire an alternating current loss of the superconducting material according to the detection current and the detection voltage.

Description

Technical Field

[0001] This invention relates to the field of testing technology for superconducting materials, and in particular to a device and method for testing the AC loss of superconducting materials. Background Technology

[0002] High-temperature superconducting materials inevitably experience AC losses under alternating current or magnetic fields. These losses are electromagnetic energy consumed as heat, converted from eddy currents and hysteresis. This heat increases the cooling load, and if not removed promptly, it can cause the superconducting device to lose its quench or even burn out. Current methods for measuring AC losses mostly employ the "transmission loss method," which involves connecting the superconducting material in series in the test circuit, injecting AC current into it, and then extracting the active component through a lock-in amplifier or integrator. However, once the sample is in coil form, its inductive reactance increases rapidly with frequency and inductance, leading to excessively high apparent power. This necessitates an AC power supply of tens of kilovolt-amperes or even megavolt-amperes, and the cooling system must dissipate a massive amount of reactive power. This is not only costly but also highly prone to introducing measurement errors.

[0003] To reduce apparent power, researchers often use series or parallel compensation capacitors or mutual inductance compensation coils. However, these "external compensation" schemes generally suffer from problems such as large component size, narrow tuning bandwidth, easy detuning after parameter drift, and overcurrent. They are particularly sensitive to high frequency and high current tests. Summary of the Invention

[0004] This invention provides an AC loss testing device and method for superconducting materials, which reduces energy consumption when detecting AC loss in superconducting materials and improves the accuracy of AC loss detection results.

[0005] According to one aspect of the present invention, an AC loss testing device for superconducting materials is provided, the superconducting material comprising a baseband buffer layer, a first superconducting layer, and a second superconducting layer, the AC loss testing device for the superconducting material comprising:

[0006] First current conductor, second current conductor, connecting conductive structure, signal detection device and AC power module;

[0007] The first current conduction band is electrically connected to the first end of the first superconducting layer, the second current conduction band is electrically connected to the first end of the second superconducting layer, and the second end of the first superconducting layer and the second end of the second superconducting layer are electrically connected through the connecting conductive structure;

[0008] The first output terminal of the AC power module is electrically connected to the first current conductor, and the second output terminal of the AC power module is electrically connected to the second current conductor; the first output terminal is used to output an L-phase power signal, and the second output terminal is used to output an N-phase power signal.

[0009] The signal detection device is configured to: acquire the detection current and detection voltage of the superconducting material when the first current conduction band receives the L-phase power signal and the second current conduction band receives the N-phase power signal, and acquire the AC loss of the superconducting material based on the detection current and the detection voltage.

[0010] Optionally, the AC power module includes a signal generator and a power amplifier;

[0011] The input terminal of the power amplifier is electrically connected to the signal generator, the first output terminal of the power amplifier is electrically connected to the first current conductor, and the second output terminal of the power amplifier is electrically connected to the second current conductor.

[0012] The signal generator is used to output the AC power signal, and the power amplifier is used to amplify the AC power signal and output it to the first current conduction band and the second current conduction band.

[0013] Optionally, the superconducting material is a superconducting tape.

[0014] Optionally, the superconducting material is a superconducting coil.

[0015] Optionally, the conductive connection structure includes: a first connecting portion, a second connecting portion, and a third connecting portion;

[0016] The first end of the first connecting portion is electrically connected to the first end of the first superconducting layer, the first end of the second connecting portion is electrically connected to the second end of the second superconducting layer, and the second end of the first connecting portion and the second end of the second connecting portion are electrically connected through the third connecting portion.

[0017] Optionally, the signal detection device is further configured to:

[0018] Obtain the first detection current of the first superconducting layer and the second detection current of the second superconducting layer;

[0019] Obtain the first inductance of the first superconducting layer, the second inductance of the second superconducting layer, and the coupling coefficient between the first superconducting layer and the second superconducting layer;

[0020] The equivalent inductance of the superconducting material is obtained based on the first inductance, the second inductance, and the coupling coefficient.

[0021] The apparent power of the superconducting material is obtained based on the first detected current and the equivalent inductance.

[0022] Alternatively, the apparent power of the superconducting material can be obtained based on the second detected current and the equivalent inductance.

[0023] Optionally, the signal detection device is further configured to:

[0024] Based on the first formula, the equivalent inductance of the superconducting material is obtained according to the first inductance, the second inductance, and the coupling coefficient.

[0025] The first formula is: Leq = (L1 + L2) × (1 - k);

[0026] Where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

[0027] According to another aspect of the present invention, a method for testing the AC loss of superconducting materials is provided, which is executed by the signal detection device in the aforementioned AC loss testing apparatus, comprising:

[0028] When the first current conduction band receives the L-phase power signal and the second current conduction band receives the N-phase power signal, the detection current and detection voltage of the superconducting material are obtained.

[0029] The AC loss of the superconducting material is obtained based on the detected current and the detected voltage.

[0030] Optionally, the AC loss testing method for the superconducting material further includes:

[0031] Obtain the first detection current of the first superconducting layer and the second detection current of the second superconducting layer;

[0032] Obtain the first inductance of the first superconducting layer, the second inductance of the second superconducting layer, and the coupling coefficient between the first superconducting layer and the second superconducting layer;

[0033] The equivalent inductance of the superconducting material is obtained based on the first inductance, the second inductance, and the coupling coefficient.

[0034] The apparent power of the superconducting material is obtained based on the first detected current and the equivalent inductance.

[0035] Alternatively, the apparent power of the superconducting material can be obtained based on the second detected current and the equivalent inductance.

[0036] Optionally, obtaining the equivalent inductance of the superconducting material based on the first inductance, the second inductance, and the coupling coefficient includes:

[0037] Based on the first formula, the equivalent inductance of the superconducting material is obtained according to the first inductance, the second inductance, and the coupling coefficient.

[0038] The first formula is: Leq = (L1 + L2) × (1 - k);

[0039] Where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

[0040] The AC loss testing device for superconducting materials provided by this invention, by setting a first current conductor electrically connected to the first end of the first superconducting layer of the superconducting material, setting a second current conductor electrically connected to the first end of the second superconducting layer of the superconducting material, and setting the second ends of the first and second superconducting layers electrically connected through a connecting conductive structure, and by setting the first current conductor to receive the L-phase power signal of the AC power signal, and the second current conductor to receive the N-phase power signal of the AC power signal, the two superconducting layers of the superconducting material can respectively receive power signals with opposite polarities from the two phase ends of the AC power supply, thereby effectively reducing the effective loss. Inductors can reduce the need for an AC signal source, allowing the use of a smaller AC power signal as the signal source when detecting the AC loss of superconducting materials. This reduces energy consumption and the heat generated by the superconducting material when AC power is applied, significantly reducing the cooling load and lowering testing costs. Furthermore, it eliminates the need for additional compensation capacitors or mutual inductance compensation coils, reducing the size of the AC loss testing device and avoiding problems such as narrow tuning bandwidth, detuning after parameter drift, and overcurrent, thus effectively improving the accuracy of AC loss test results.

[0041] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of an AC loss testing device for superconducting materials provided in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of another AC loss testing device for superconducting materials provided in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the structure of another AC loss testing device for superconducting materials provided in an embodiment of the present invention;

[0046] Figure 4This is a schematic diagram of the structure of another AC loss testing device for superconducting materials provided in an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the AC loss testing method for superconducting materials in the existing technology;

[0048] Figure 6 This is a flowchart of an AC loss testing method for superconducting materials provided in an embodiment of the present invention;

[0049] Figure 7 This is a flowchart of another AC loss testing method for superconducting materials provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] Figure 1 This is a schematic diagram of the structure of an AC loss testing device for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 1As shown, the superconducting material 20 includes: a baseband buffer layer 21, a first superconducting layer 22, and a second superconducting layer 23; the first superconducting layer 22 and the second superconducting layer 23 are located on opposite sides of the baseband buffer layer 21. The AC loss testing device 10 for superconducting materials includes: a first current conductor 11, a second current conductor 12, a connecting conductive structure 13, a signal detection device 14, and an AC power module 15. The first current conductor 11 is electrically connected to the first end of the first superconducting layer 22, the second current conductor 12 is electrically connected to the first end of the second superconducting layer 23, and the second end of the first superconducting layer 22 and the second end of the second superconducting layer 23 are electrically connected through the connecting conductive structure 13. The first output terminal of the AC power module 15 is electrically connected to the first current conductor 11, and the second output terminal of the AC power module 15 is electrically connected to the second current conductor 12. The first output terminal is used to output the L-phase power signal EL, and the second output terminal is used to output the N-phase power signal EN. The signal detection device 14 is configured to: acquire the detection current and detection voltage of the superconducting material 20 when the first current conductor 11 receives the L-phase power signal EL and the second current conductor 12 receives the N-phase power signal EN, and acquire the AC loss of the superconducting material 20 based on the detection current and detection voltage.

[0053] Specifically, in the superconducting material 20, the baseband buffer layer 21 includes a baseband layer and a buffer layer (not shown in the figure). The baseband layer is mainly composed of a high-strength metal baseband, which is used to provide relatively high mechanical strength and stability for the first superconducting layer 22 and the second superconducting layer 23, ensuring that the superconducting material 20 is not easily deformed or damaged during application. The buffer layer can be disposed between the baseband layer and the superconducting layer. For example, the buffer layer can include a first buffer layer and a second buffer layer. The first buffer layer can be disposed between the baseband layer and the first superconducting layer 22, and the second buffer layer can be disposed between the baseband layer and the second superconducting layer 23. This reduces stress concentration during the growth process of the first superconducting layer 22 and the second superconducting layer 23, promotes the bonding between the superconducting layer and the baseband layer, and prevents the diffusion of metal atoms from the baseband layer to the superconducting layer. It can also prevent the diffusion of oxygen atoms from the superconducting layer to the baseband layer. In addition, the buffer layer can also serve as an insulating layer to achieve insulation between the first superconducting layer 22 and the second superconducting layer 23, which is beneficial to improving the stability and reliability of the superconducting material.

[0054] For example, the superconducting material 20 tested by the AC loss testing device 10 for superconducting materials can be as follows: Figure 1 The superconducting tape shown is a long, strip-shaped structure. Alternatively, Figure 2 This is a schematic diagram of another AC loss testing device for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the superconducting material 20 can also be a superconducting coil, specifically a double-pancake coil. This embodiment of the invention does not specifically limit this.

[0055] The AC loss testing device 10 for superconducting materials includes a first current conductor 11, a second current conductor 12, a connecting conductive structure 13, a signal detection device 14, and an AC power module 15. It is understood that the first current conductor 11, the second current conductor 12, and the connecting conductive structure 13 are all conductive structures capable of transmitting electrical signals. Specifically, the first current conductor 11 can be configured to contact the first end of the first superconducting layer 22 to achieve electrical connection, the second current conductor 12 can be configured to contact the first end of the second superconducting layer 23 to achieve electrical connection, and one end of the connecting conductive structure 13 can be configured to contact the second end of the first superconducting layer 22 to achieve electrical connection, and the other end of the connecting conductive structure 13 can be configured to contact the second end of the second superconducting layer 23 to achieve electrical connection, so that the first superconducting layer 22 and the superconducting layer 23 are electrically connected through the connecting conductive structure 13.

[0056] For example, the first current conducting strip 11 and the second current conducting strip 12 can also be elongated strip structures. When the first current conducting strip 11 is in contact with the first end of the first superconducting layer 22, a portion of the first current conducting strip 11 can be located on the side of the first superconducting layer 22 away from the second superconducting layer 23, and in contact with the end of the first end of the first superconducting layer 22. Similarly, when the second current conducting strip 12 is in contact with the first end of the second superconducting layer 23, a portion of the second current conducting strip 12 can be located on the side of the second superconducting layer 23 away from the first superconducting layer 22, and in contact with the end of the first end of the second superconducting layer 23.

[0057] For example, the conductive connection structure 13 includes: a first connection portion 131, a second connection portion 132, and a third connection portion 133; the first end of the first connection portion 131 is electrically connected to the second end of the first superconducting layer 22, the first end of the second connection portion 132 is electrically connected to the second end of the second superconducting layer 23, and the second end of the first connection portion 131 and the second end of the second connection portion 132 are electrically connected through the third connection portion 133.

[0058] Specifically, the conductive connection structure 13 may include a first connecting portion 131, a second connecting portion 132, and a third connecting portion 133. When the two ends of the conductive connection structure 13 are respectively in contact with the second end of the first superconducting layer 22 and the second end of the second superconducting layer 23, the end of the first end of the first connecting portion 131 may be located on the side of the first superconducting layer 22 away from the second superconducting layer 23 and in contact with the end of the second end of the first superconducting layer 22; the end of the first end of the second connecting portion 132 may be located on the side of the second superconducting layer 23 away from the first superconducting layer 22 and in contact with the end of the second end of the second superconducting layer 23; the two ends of the third connecting portion 133 may be in contact with the end of the second end of the first connecting portion 131 and the end of the second end of the second connecting portion 132, respectively, and the third connecting portion 133 does not contact the superconducting material 20. Thus, the second end of the first superconducting layer 22 is electrically contacted with the second end of the second superconducting layer 23 through the first connecting portion 131, the third connecting portion 133, and the second connecting portion 132 in sequence.

[0059] The first current conduction band 11 and the second current conduction band 12 are used to receive power signals. Based on the requirement to detect the AC loss of the superconducting material 20, the first current conduction band 11 and the second current conduction band 12 can be set to receive AC power signals. One of them can be set to receive the L-phase power signal EL, and the other can receive the N-phase power signal EN. An AC power module 15 can be configured to provide AC power, such that the first output terminal of the AC power module 15 outputting the L-phase power signal EL is electrically connected to the first current conductor 11, and the second output terminal outputting the N-phase power signal EN is electrically connected to the second current conductor 12, so that the first current conductor 11 and the second current conductor 12 can respectively receive the L-phase power signal EL and the N-phase power signal EN of the AC power. When the first current conductor 11 and the second current conductor 12 respectively receive the L-phase power signal EL and the N-phase power signal EN of the AC power, the current flow is as follows: the first output terminal of the AC power module 15, the first current conductor 11, the first superconducting layer 22, the connecting conductive structure 13, the second superconducting layer 23, the second current conductor 12, and the second output terminal of the AC power module 15. The currents flowing through the first superconducting layer 22 and the second superconducting layer 23 are of the same magnitude but opposite in direction. Because the first superconducting layer 22 and the second superconducting layer 23 are relatively close (only a baseband buffer layer 21 is provided between them) and have the same geometry, the mutual inductive coupling between them is large. This causes the mutual inductance of the first superconducting layer 22 and the second superconducting layer 23 to cancel each other out, significantly reducing the equivalent inductance of the superconducting material. This effectively reduces the apparent power of the superconducting material when detecting AC losses, thereby reducing the voltage level of the AC signal source and enabling better detection of AC losses in the superconducting material. Using an AC power signal with a small voltage amplitude as the signal source can reduce energy consumption and the heat generated by the superconducting material when AC power is applied, thereby significantly reducing the cooling load on the superconducting material and further reducing energy consumption. It also helps to reduce testing costs. In addition, it eliminates the need for additional compensation capacitors or mutual inductance compensation coils, or only requires series capacitors with small capacitance values ​​for compensation. This reduces the size of the AC loss testing device 10 for superconducting materials and avoids problems such as narrow tuning bandwidth, easy detuning after parameter drift, and overcurrent, effectively improving the accuracy of AC loss test results.

[0060] For example, the AC loss testing device 10 for superconducting materials may further include a current sensor 16. The signal detection device 14 can detect the current signal (i.e., the detection current) of the superconducting material 20 through the current sensor 16. The current sensor is connected in series in the AC circuit of the superconducting material 20. For example, the current sensor can be electrically connected between the first output terminal of the AC power module 15 and the first current conductor 11 (not shown in the figure), or the current sensor can be electrically connected between the second output terminal of the AC power module 15 and the second current conductor 12. For example, the current sensor can be a Rogowski coil, a zero flux sensor, or a precision shunt. Furthermore, the signal detection device 13 may include two voltage detection terminals. When detecting the voltage signal of the superconducting material (i.e., detecting the voltage), the two voltage detection terminals can be electrically connected to the first current conductor 11 and the second current conductor 12, respectively, or the two voltage detection terminals can be electrically connected to the first superconducting layer 22 or the second superconducting layer 23, respectively (not shown in the figure). The voltage difference between the two voltage detection terminals is the detection voltage. When electrically connecting the voltage detection terminals to the first current conduction band 11 and the second current conduction band 12, the connection positions can be set close to the superconducting material 20 to improve the accuracy of the detected voltage signals. The voltage and current detection signals can be acquired using the same clock to ensure they are acquired at the same time point, improving data precision and accuracy. Simultaneously, a sampling frequency greater than 10 times the test frequency can be set; the test frequency can be understood as the frequency used to calculate AC loss. This ensures the amplitude accuracy of the voltage and current detection signals and guarantees sufficient data volume to ensure the accuracy of the AC loss calculation results. After acquiring the detected voltage and current, the signal detection device 14 can integrate the product of the detected current and voltage to obtain the AC loss of the superconducting material. The formula for calculating AC loss is: Where P is the AC loss, T and t are both time, and u s (t) represents the detection voltage, i s (t) represents the detected current.

[0061] The AC loss testing device for superconducting materials provided in this embodiment of the invention, by setting a first current conductor electrically connected to the first end of the first superconducting layer of the superconducting material, setting a second current conductor electrically connected to the first end of the second superconducting layer of the superconducting material, and setting the second ends of the first and second superconducting layers electrically connected through a connecting conductive structure, and by setting the first current conductor to receive the L-phase power signal of the AC power signal, and the second current conductor to receive the N-phase power signal of the AC power signal, enables the two superconducting layers of the superconducting material to receive power signals with opposite polarities from the two phase ends of the AC power supply, thereby effectively reducing the AC loss of the superconducting material. The efficient inductance reduces the need for an AC signal source, allowing the use of a smaller AC power signal when testing the AC loss of superconducting materials. This reduces energy consumption and heat generation in the superconducting material when AC power is applied, significantly lowering the cooling load and reducing testing costs. Furthermore, it eliminates the need for additional compensation capacitors or mutual inductance compensation coils, reducing the size of the AC loss testing device and avoiding issues such as narrow tuning bandwidth, detuning due to parameter drift, and overcurrent, thus effectively improving the accuracy of AC loss test results.

[0062] For example, Figure 3 This is a schematic diagram of the structure of another AC loss testing device for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the superconducting material 20 may further include a first stabilizing layer 24 and a second stabilizing layer 25; the first stabilizing layer 24 is located on the side of the first superconducting layer 22 away from the baseband buffer layer 21; the second stabilizing layer 25 is located on the side of the second superconducting layer 23 away from the baseband buffer layer 21. The first stabilizing layer 24 and the second stabilizing layer 25 may include copper and / or silver, which can improve the conductivity of the superconducting material, improve the mechanical properties of the superconducting material to enhance its bending resistance, and isolate the superconducting layer from the external environment, thus helping to extend the service life of the superconducting material.

[0063] When the superconducting material 20 includes a first stabilizing layer 24 and a second stabilizing layer 25, a first current conducting band 11 can be made to contact the first end of the first stabilizing layer 24 to achieve electrical connection, a second current conducting band 12 can be made to contact the first end of the second stabilizing layer 25 to achieve electrical connection, and one end of the connecting conductive structure 13 can be made to contact the second end of the first stabilizing layer 24 to achieve electrical connection, and the other end of the connecting conductive structure 13 can be made to contact the second end of the second stabilizing layer 25 to achieve electrical connection, so that the first stabilizing layer 24 and the second stabilizing layer 25 are electrically connected through the connecting conductive structure 13.

[0064] Specifically, when the first current conductor 11 is in contact with the first end of the first stabilizing layer 24, a portion of the first current conductor 11 can be located on the side of the first stabilizing layer 24 away from the first superconducting layer 22, and in contact with the end of the first end of the first stabilizing layer 24. Similarly, when the second current conductor 12 is in contact with the first end of the second stabilizing layer 25, a portion of the second current conductor 12 can be located on the side of the second stabilizing layer 25 away from the second superconducting layer 23, and in contact with the end of the first end of the second stabilizing layer 25. When the first current conductor 11 and the second current conductor 12 receive the L-phase power signal EL and the N-phase power signal EN of the AC power supply, respectively, the current flow is as follows: first output terminal of AC power module 15, first current conductor 11, first stabilizing layer 24, first superconducting layer 22, first stabilizing layer 24, connecting conductive structure 13, second stabilizing layer 25, second superconducting layer 23, second stabilizing layer 25, second current conductor 12, second output terminal of AC power module 15. Similarly, this allows the current flowing through the first superconducting layer 22 and the second superconducting layer 23 to be of the same magnitude but in opposite directions. It also effectively reduces the apparent power when detecting the AC loss of the superconducting material 20 and effectively improves the accuracy of the AC loss test results. Optionally, Figure 4 This is a schematic diagram of the structure of another AC loss testing device for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the AC power supply unit 15 includes a signal generator 151 and a power amplifier 152; the input terminal of the power amplifier 152 is electrically connected to the signal generator 151, the first output terminal of the power amplifier 152 is electrically connected to the first current conduction band 11, and the second output terminal of the power amplifier 152 is electrically connected to the second current conduction band 12; the signal generator 151 is used to output an AC power signal, and the power amplifier 152 is used to amplify the AC power signal and output it to the first current conduction band 11 and the second current conduction band 12.

[0065] Specifically, an AC power module 15 can be configured to provide AC power to the superconducting material 20. The power module 15 may include a signal generator 151 and a power amplifier 152. The frequency of the AC power output by the signal generator 151 is adjustable, and the power amplifier 152 can amplify the power of the AC power output by the signal generator 151. The first output terminal of the power amplifier 152 can be an L-phase power output terminal, so its output signal can be an L-phase power signal EL. Its second output terminal can be an N-phase power output terminal, so its output signal can be an N-phase power signal EN. Thus, the first output terminal can be electrically connected to the first current conductor 11 to provide the L-phase power signal EL, and the second output terminal can be electrically connected to the second current conductor 12 to provide the N-phase power signal EN.

[0066] Based on this, when detecting the AC loss of superconducting materials, the apparent power of the superconducting materials can also be detected by the signal detection device 14.

[0067] For example, the signal detection device 14 is also configured to implement the following method steps:

[0068] S1. Obtain the first detection current I1 of the first superconducting layer 22 and the second detection current I2 of the second superconducting layer 23.

[0069] Specifically, if the current sensor 16 is positioned between the first output terminal of the AC power module 15 and the first current conductor 11, the current signal detected by the current sensor 16 is the first detection current I1 of the first superconducting layer 22. In this case, the second detection current I2 flowing through the second superconducting layer 23 can be considered to have the same amplitude and phase as the first detection current I1, but opposite directions, i.e., I2 = -I1. Alternatively, if the current sensor 16 is positioned between the second output terminal of the AC power module 15 and the second current conductor 12, the current signal detected by the current sensor 16 is the second detection current I2 of the second superconducting layer 23. In this case, the first detection current I1 flowing through the first superconducting layer 22 can be considered to have the same amplitude and phase as the second detection current I2, but opposite directions, i.e., I1 = -I2.

[0070] S2. Obtain the first inductance L1 of the first superconducting layer 22, the second inductance L2 of the second superconducting layer 23, and the coupling coefficient k between the first superconducting layer 22 and the second superconducting layer 23.

[0071] Specifically, given the close proximity of the first superconducting layer 22 and the second superconducting layer 23, and the fact that the first detection current I1 of the first superconducting layer 22 and the second detection current I2 of the second superconducting layer 23 are of the same magnitude but opposite in direction, the coupling coefficient k can take a large value, especially for superconducting coils, where the coupling coefficient k approaches 1. This embodiment of the invention uses k=0.95 as an example for illustrative explanation.

[0072] S3. Obtain the equivalent inductance Leq of the superconducting material 20 based on the first inductance L1, the second inductance L2 and the coupling coefficient k.

[0073] For example, based on the first formula, the equivalent inductance Leq of the superconducting material is obtained according to the first inductance L1, the second inductance L2, and the coupling coefficient k. The first formula is: Leq=(L1+L2)×(1-k); where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

[0074] Specifically, assuming the frequency of the AC power signal is ω, the first detection current I1 and the second detection current I2 are respectively: I1 = I0 × sinωt, I2 = -I0 × sinωt, where I0 is the current amplitude. Assuming the mutual inductance between the first superconducting layer 22 and the second superconducting layer 23 is M, the first induced voltage of the first superconducting layer 22 is V1, and the second induced voltage of the second superconducting layer 23 is V2, then the first induced voltage V1 and the second induced voltage V2 satisfy: V1 = L1 × (dI1 / dt) + M × (dI2 / dt), V2 = L2 × (dI2 / dt) + M × (dI1 / dt). Substituting I2 = -I1, we get: V1 = (L1 - M) × (dI1 / dt), V2 = (L2 - M) × (dI2 / dt). Therefore, the equivalent voltage Veq between the first and second ends of the superconducting material is V1 - V2 = (L1 + L2 - 2 × M) × (dI1 / dt). Thus, the equivalent inductance Leq can be defined as L1 + L2 - 2 × M. If the first inductance L1 of the first superconducting layer 22 and the second inductance L2 of the second superconducting layer 23 are both L, and the coupling coefficient k = M / L, then the equivalent inductance Leq can be expressed as: Leq = (L1 + L2) × (1 - k) = 2 × L × (1 - k). Therefore, given the first inductance L1, the second inductance L2, and the coupling coefficient k, the equivalent inductance Leq of the superconducting material can be calculated based on the first formula.

[0075] S4. Obtain the apparent power Seq of the superconducting material 20 based on the first detection current I1 and the equivalent inductance Leq; or, obtain the apparent power Seq of the superconducting material 20 based on the second detection current I2 and the equivalent inductance Leq.

[0076] Specifically, the amplitudes of the first detection current I1 and the second detection current I2 are equal. Therefore, the apparent power Seq of the superconducting material 20 can be obtained based on the first detection current I1 and the equivalent inductance Leq, and vice versa. Assuming the amplitude of the first detection current I1 and the second detection current I2 is I0, then the apparent power Seq = I0 × (2 × π × f × Leq). Assuming k = 0.95, then the apparent power Seq = I0 × 2 × π × f × [2 × L × (1-k)] = 0.1 × (I0 × 2 × π × f × L). It can be understood that the AC loss of the superconducting material is active power, and the apparent power is the sum of active and reactive power. Thus, when detecting the AC loss of the superconducting material, the apparent power can be detected simultaneously to assess the impact of the apparent power on the AC loss detection results.

[0077] For example, Figure 5 This is a schematic diagram of existing methods for testing the AC loss of superconducting materials, such as... Figure 5As shown, the superconducting material 20 is connected in series between the L-phase and N-phase terminals of the AC power supply Uac, so that one end receives the L-phase power signal EL and the other end receives the N-phase power signal EN. Assuming the inductance of the superconducting material is L, when detecting AC losses using the same AC power signal, the apparent power S0 of the superconducting material in the prior art is S0 = I0 × 2 × π × f × L. Compared to the prior art, the apparent power Seq and S0 of the superconducting material detected in this embodiment and the prior art satisfy Seq = 0.1 × S0. This reduces the required reactive voltage from hundreds of kilovolts to tens of volts, significantly improves the AC power factor, greatly reduces the test power and cooling load, and makes the AC loss test results more accurate.

[0078] In summary, the AC loss testing device for superconducting materials provided in this embodiment of the invention can significantly reduce the apparent power when detecting the AC loss of superconducting materials, thereby reducing the demand for AC power. In other words, a smaller AC power signal can be used to meet the AC loss detection requirements. Furthermore, due to the significant reduction in apparent power, the interference of reactive power on AC loss is greatly reduced, which can effectively improve the accuracy of AC loss detection.

[0079] In this embodiment of the invention, the effective inductance is significantly reduced, resulting in a decrease in reactive power and a substantial reduction in the apparent power of the superconducting material. This allows for a reduction in the voltage level of the AC signal source, which is beneficial for reducing energy consumption. Furthermore, due to the reduced apparent power, a smaller measuring device can be used to detect the voltage and current signals. Since the AC loss of the superconducting material is constant, the reduction in apparent power increases the proportion of AC loss, thereby increasing the resolution of the measuring device for the voltage and current signals and effectively improving measurement accuracy. This, in turn, contributes to improving the accuracy of the AC loss detection results.

[0080] Based on the same inventive concept, embodiments of the present invention also provide a method for testing the AC loss of superconducting materials, which is executed by the signal detection device in the AC loss testing apparatus provided in any embodiment of the present invention.

[0081] Figure 6 This is a flowchart of an AC loss testing method for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the AC loss testing method for this superconducting material includes:

[0082] S110. When receiving the L-phase power signal in the first current conduction band and the N-phase power signal in the second current conduction band, the detection current and detection voltage of the superconducting material are obtained.

[0083] S120. Obtain the AC loss of the superconducting material based on the detection current and detection voltage.

[0084] The AC loss testing method for superconducting materials provided in this invention can effectively reduce the effective inductance and the requirement for an AC signal source. Therefore, when detecting the AC loss of superconducting materials, a smaller AC power signal can be used as the signal source. This reduces energy consumption and the heat generated by the superconducting material when AC power is applied, significantly reducing the cooling load on the superconducting material and lowering testing costs. Furthermore, it eliminates the need for additional compensation capacitors or mutual inductance compensation coils, reducing the size of the AC loss testing device 10. It also avoids problems such as narrow tuning bandwidth, easy detuning after parameter drift, and overcurrent, effectively improving the accuracy of the AC loss test results.

[0085] Optional, Figure 7 This is a flowchart of another AC loss testing method for superconducting materials provided in an embodiment of the present invention, as shown below. Figure 7 As shown, the AC loss testing method for this superconducting material includes:

[0086] S210. When receiving the L-phase power signal in the first current conduction band and the N-phase power signal in the second current conduction band, the detection current and detection voltage of the superconducting material are obtained.

[0087] S220. Obtain the AC loss of the superconducting material based on the detection current and detection voltage.

[0088] S230, Obtain the first detection current of the first superconducting layer and the second detection current of the second superconducting layer.

[0089] S240, Obtain the first inductance of the first superconducting layer, the second inductance of the second superconducting layer, and the coupling coefficient between the first superconducting layer and the second superconducting layer.

[0090] S250. Obtain the equivalent inductance of the superconducting material based on the first inductance, the second inductance, and the coupling coefficient.

[0091] For example, the equivalent inductance of a superconducting material can be obtained based on a first formula, according to a first inductance, a second inductance, and a coupling coefficient.

[0092] The first formula is: Leq=(L1+L2)×(1-k); where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

[0093] S260. Obtain the apparent power of the superconducting material based on the first detection current and the equivalent inductance; or, obtain the apparent power of the superconducting material based on the second detection current and the equivalent inductance.

[0094] The AC loss testing method for superconducting materials provided in this invention can simultaneously detect the apparent power of superconducting materials when detecting their AC loss, which is beneficial for evaluating the impact of apparent power on the AC loss detection results.

[0095] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An AC loss testing device for a superconducting material, the superconducting material comprising a baseband buffer layer, a first superconducting layer, and a second superconducting layer, wherein the first superconducting layer and the second superconducting layer are located on opposite sides of the baseband buffer layer, characterized in that, The AC loss testing device for the superconducting material includes: First current conductor, second current conductor, connecting conductive structure, signal detection device, AC power module and current sensor; The first current conduction band is electrically connected to the first end of the first superconducting layer, the second current conduction band is electrically connected to the first end of the second superconducting layer, and the second end of the first superconducting layer and the second end of the second superconducting layer are electrically connected through the connecting conductive structure; The first output terminal of the AC power module is electrically connected to the first current conductor, and the second output terminal of the AC power module is electrically connected to the second current conductor; the first output terminal is used to output an L-phase power signal, and the second output terminal is used to output an N-phase power signal. The signal detection device includes two voltage detection terminals, which are electrically connected to the first current conduction band and the second current conduction band, respectively. The voltage difference between the two voltage detection terminals is the detection voltage. The current sensor is electrically connected between the first output terminal of the AC power module and the first current conductor, or the current sensor is electrically connected between the second output terminal of the AC power module and the second current conductor; the signal detection device detects the detection current of the superconducting material through the current sensor; The signal detection device is configured to: acquire the detection current and detection voltage of the superconducting material when the first current conduction band receives the L-phase power signal and the second current conduction band receives the N-phase power signal, and acquire the AC loss of the superconducting material based on the detection current and the detection voltage.

2. The AC loss testing device for superconducting materials according to claim 1, characterized in that, The AC power module includes a signal generator and a power amplifier; The input terminal of the power amplifier is electrically connected to the signal generator, the first output terminal of the power amplifier is electrically connected to the first current conductor, and the second output terminal of the power amplifier is electrically connected to the second current conductor. The signal generator is used to output the AC power signal, and the power amplifier is used to amplify the AC power signal and output it to the first current conduction band and the second current conduction band.

3. The AC loss testing device for superconducting materials according to claim 1, characterized in that, The superconducting material is a superconducting tape.

4. The AC loss testing device for superconducting materials according to claim 1, characterized in that, The superconducting material is a superconducting coil.

5. The AC loss testing device for superconducting materials according to claim 1, characterized in that, The conductive connection structure includes: a first connecting portion, a second connecting portion, and a third connecting portion; The first end of the first connecting portion is electrically connected to the first end of the first superconducting layer, the first end of the second connecting portion is electrically connected to the second end of the second superconducting layer, and the second end of the first connecting portion and the second end of the second connecting portion are electrically connected through the third connecting portion.

6. The AC loss testing device for superconducting materials according to claim 1, characterized in that, The signal detection device is further configured to: Obtain the first detection current of the first superconducting layer and the second detection current of the second superconducting layer; Obtain the first inductance of the first superconducting layer, the second inductance of the second superconducting layer, and the coupling coefficient between the first superconducting layer and the second superconducting layer; The equivalent inductance of the superconducting material is obtained based on the first inductance, the second inductance, and the coupling coefficient. The apparent power of the superconducting material is obtained based on the first detected current and the equivalent inductance. Alternatively, the apparent power of the superconducting material can be obtained based on the second detected current and the equivalent inductance.

7. The AC loss testing device for superconducting materials according to claim 6, characterized in that, The signal detection device is further configured to: Based on the first formula, the equivalent inductance of the superconducting material is obtained according to the first inductance, the second inductance, and the coupling coefficient. The first formula is: Leq = (L1 + L2) × (1 - k); Where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

8. A method for testing the AC loss of a superconducting material, performed by the signal detection device in the AC loss testing apparatus according to any one of claims 1 to 7, characterized in that, include: When the first current conduction band receives the L-phase power signal and the second current conduction band receives the N-phase power signal, the detection current and detection voltage of the superconducting material are obtained. The AC loss of the superconducting material is obtained based on the detected current and the detected voltage. The formula for calculating the AC loss is: Where P is the AC loss, T and t are both time, and u s (t) represents the detection voltage, i s (t) represents the detected current.

9. The AC loss testing method for superconducting materials according to claim 8, characterized in that, Also includes: Obtain the first detection current of the first superconducting layer and the second detection current of the second superconducting layer; Obtain the first inductance of the first superconducting layer, the second inductance of the second superconducting layer, and the coupling coefficient between the first superconducting layer and the second superconducting layer; The equivalent inductance of the superconducting material is obtained based on the first inductance, the second inductance, and the coupling coefficient. The apparent power of the superconducting material is obtained based on the first detected current and the equivalent inductance. Alternatively, the apparent power of the superconducting material can be obtained based on the second detected current and the equivalent inductance.

10. The AC loss testing method for superconducting materials according to claim 9, characterized in that, Obtaining the equivalent inductance of the superconducting material based on the first inductance, the second inductance, and the coupling coefficient includes: Based on the first formula, the equivalent inductance of the superconducting material is obtained according to the first inductance, the second inductance, and the coupling coefficient. The first formula is: Leq = (L1 + L2) × (1 - k); Where Leq is the equivalent inductance, L1 is the first inductance, L2 is the second inductance, and k is the coupling coefficient.

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