Charging control method and computer device for high temperature superconducting non-insulated coil

Abstract

The present invention relates to the field of nuclear fusion technology, and discloses a charging control method for a high-temperature superconducting non-insulated coil and a computer device. The method comprises: when charging is started, controlling the charging current of the high-temperature superconducting non-insulated coil to rise to a maximum limiting current value at a fixed current rise rate; wherein the maximum limiting current value is greater than the working current value of the coil; when the charging current rises to the maximum limiting current value, suddenly changing the charging current to the working current value of the coil and maintaining it at the working current value; the above method does not need to change the coil structure, does not affect the coil preparation process, and retains the self-protection capability and simple preparation characteristics of the high-temperature superconducting non-insulated coil; and by controlling the charging current to maintain a flat-top current value within a preset time length, the purpose of fast charging of the high-temperature superconducting non-insulated coil can be achieved on the basis of retaining the self-protection capability of the high-temperature superconducting non-insulated coil.

Description

Technical Field

[0001] The invention relates to the field of nuclear fusion technology, and in particular to a charging control method for a high-temperature superconducting non-insulated coil and a computer device. Background Art

[0002] High-temperature superconducting uninsulated coils have the advantages of high current density and good stability, and are widely used in fusion magnets, accelerator magnets, medical magnets and other fields. However, due to the small turn-to-turn resistance and large inductance of high-temperature superconducting uninsulated coils, when charging high-temperature superconducting uninsulated coils, the rate at which current enters the superconducting tape is slow, and it often takes several hours or even days to reach the operating current, resulting in higher coil operating costs. Therefore, it is very important to achieve fast charging of high-temperature superconducting uninsulated coils.

[0003] At present, the commonly used methods to improve the charging speed of high-temperature superconducting uninsulated coils are to increase the current rise rate, increase the inter-turn resistance and circuit feedback control; increasing the current rise rate will cause the coil to heat up more seriously and there is a risk of burning. Increasing the inter-turn resistance is mainly achieved through parallel winding and impregnation, which often makes the coil preparation process more complicated and leads to a decrease in thermal and mechanical stability, which is contrary to the self-protection characteristics of high-temperature superconducting uninsulated coils. Circuit feedback control requires a relatively complex external circuit to monitor the coil magnetic field in real time and feedback control the current rate. The risk of the feedback control process is difficult to assess and is of little significance in low temperature conditions.

[0004] Therefore, how to simply reduce the charging time of high-temperature superconducting uninsulated coils has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a charging control method for a high-temperature superconducting non-insulated coil and a computer device to solve the technical problem of slow charging speed of the charging control method for a high-temperature superconducting non-insulated coil.

[0006] In a first aspect, the present invention provides a charging control method for a high-temperature superconducting uninsulated coil, comprising: at the start of charging, controlling the charging current of the high-temperature superconducting uninsulated coil to rise to a maximum limiting current value at a fixed current rise rate; wherein the maximum limiting current value is greater than the working current value of the coil; when the charging current rises to the maximum limiting current value, suddenly changing the charging current to the working current value of the coil and maintaining it at the working current value.

[0007] In a second aspect, the present invention also provides a charging control method for a high-temperature superconducting uninsulated coil, comprising: at the start of charging, controlling the charging current of the high-temperature superconducting uninsulated coil to rise to a flat-top current value at a preset current rise rate; the flat-top current value is greater than the working current value of the high-temperature superconducting uninsulated coil; within a preset time length, controlling the charging current to maintain the flat-top current value; when the preset time length is reached, controlling the charging current to drop to the working current value of the high-temperature superconducting uninsulated coil according to a preset current drop rate.

[0008] As an exemplary embodiment, when the charging current is controlled to increase at the preset current rise rate, the actual heating power of the high-temperature superconducting non-insulated coil is less than the preset heating power.

[0009] As an exemplary embodiment, the preset heating power is less than or equal to the maximum allowable heating power during the operation of the high-temperature superconducting uninsulated coil, wherein the maximum allowable heating power is less than or equal to the actual cooling capacity provided by the refrigeration equipment during the operation of the high-temperature superconducting uninsulated coil acting on the high-temperature superconducting uninsulated coil.

[0010] As an exemplary embodiment, the preset upflow rate and the preset downflow rate are equal.

[0011] As an exemplary embodiment, the flat-top current value is less than 0.8 times the critical current value of the high-temperature superconducting uninsulated coil.

[0012] As an exemplary embodiment, the method for determining the flat-top current value and the preset duration includes: obtaining coil parameters of the high-temperature superconducting non-insulated coil, the coil parameters including coil inductance and turn-to-turn resistance; determining a preset rising current rate interval and a preset falling current rate interval corresponding to a maximum allowable heating power corresponding to the high-temperature superconducting non-insulated coil based on a heat generation power calculation formula during current changes of the high-temperature superconducting non-insulated coil; and using an enumeration method to determine a flat-top current value that can shorten the charging time of the high-temperature superconducting non-insulated coil and a duration of the flat-top current value within the preset rising current rate interval, the preset falling current rate interval and the interval of the flat-top current value.

[0013] As an exemplary embodiment, the method further includes: before charging is started, after a test current is passed into the high-temperature superconducting non-insulated coil, a test result of the high-temperature superconducting non-insulated coil is obtained.

[0014] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the charging control method for a high-temperature superconducting uninsulated coil according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the charging control method for a high-temperature superconducting uninsulated coil according to the first aspect or any corresponding embodiment thereof.

[0016] This application has at least the following beneficial effects:

[0017] When charging starts, the charging current of the high-temperature superconducting non-insulated coil is controlled to rise to the maximum limiting current value at a fixed current rise rate; wherein the maximum limiting current value is greater than the working current value of the coil; when the charging current rises to the maximum limiting current value, the charging current is suddenly changed to the working current value of the coil and maintained at the working current value. Controlling the charging current to rise above the working current of the coil and performing overcurrent charging can enable the charging current of the coil to continue to grow linearly, allowing the charging current of the coil to quickly reach or even exceed the working current, and then reducing the charging current value to the working current value in the form of a sudden change. At this time, the current on the inter-turn resistance decreases rapidly, and the current quickly becomes almost entirely through the coil, which is manifested as a rapid decrease in the coil voltage and a significant reduction in the charging time of the coil.

[0018] Furthermore, when charging is started, the charging current of the high-temperature superconducting non-insulated coil is controlled to rise to a flat-top current value at a preset current rise rate; the flat-top current value is greater than the working current value of the high-temperature superconducting non-insulated coil; within a preset time period, the charging current is controlled to maintain the flat-top current value; when the preset time period is reached, the charging current is controlled to decrease to the working current value of the high-temperature superconducting non-insulated coil according to a preset current reduction rate; the above control method does not require changing the coil structure, does not affect the coil preparation process, and retains the self-protection ability and simple preparation characteristics of the high-temperature superconducting non-insulated coil; and, by controlling the charging current to maintain the flat-top current value within the preset time period, the purpose of fast charging of the high-temperature superconducting non-insulated coil can be achieved on the basis of retaining the self-protection ability of the high-temperature superconducting non-insulated coil. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] Figure 1 It is an equivalent circuit diagram of a high-temperature superconducting non-insulated coil in the related art;

[0021] Figure 2 It is a schematic flow chart of a charging control method for a high-temperature superconducting non-insulated coil according to Embodiment 1 of the present invention;

[0022] Figure 3 is a flow chart of a charging control method for a high-temperature superconducting non-insulated coil according to a second embodiment of the present invention;

[0023] Figure 4 This is the current and heat generation power variation diagram of the high-temperature superconducting non-insulated coil in the stage with flat top and the stage without flat top;

[0024] Figure 5 It is the inter-turn current of the high-temperature superconducting uninsulated coil in the stage with flat top and the stage without flat top;

[0025] Figure 6 is a schematic diagram of the change of current over time under the charging control method of the high-temperature superconducting non-insulated coil in the second embodiment of the present invention;

[0026] Figure 7 is a schematic diagram of voltage variation over time according to the charging control method of a high-temperature superconducting non-insulated coil in Embodiment 2 of the present invention;

[0027] Figure 8 is a voltage diagram of the magnetic field changing with time under the charging control method of the high-temperature superconducting non-insulated coil in the second embodiment of the present invention;

[0028] Fig. 9 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0030] High-temperature superconducting uninsulated coils (hereinafter referred to as coils) have the advantages of high current density and good stability, and are widely used in fusion magnets, accelerator magnets, medical magnets and other fields; Figure 1 is the equivalent circuit diagram of the coil during the charging process, such as Figure 1 As shown, when the coil is charging, it can be equivalent to the inductance and the inter-turn resistance in parallel. The voltage across the inductance and the resistance is equal, and we can get:

[0031]

[0032] Wherein, L represents the coil inductance, Isc represents the coil charging current on the superconducting tape in the coil, I(t) represents the charging current, and Rc represents the turn-to-turn resistance.

[0033] When the coil is being charged with a gradually increasing charging current, the charging current is: I(t)=kt, where k is the current rise rate. Before the charging current I(t) reaches the working current of the coil, the charging current of the coil is:

[0034] Isc =kt-kτ(1-e^(-t / τ)), where the time constant τ=L / Rc.

[0035] In the prior art, before the charging current reaches the working current of the coil, the charging current of the coil increases linearly; after the charging current reaches the working current value of the coil, the working current value is maintained and a stable stage is entered until the charging current of the coil approaches the working current (for example, the charging current reaches more than 99% of the working current, or more than 99.9%, which can be determined according to actual working conditions), and the charging is considered to be completed.

[0036] According to the charging method in the prior art, after the charging current reaches the working current value of the coil, the charging current in the coil is Isc=I op (1-e^(-t / τ)), where I op is the working current value of the coil; it can be seen that after the charging current reaches the working current value of the coil, as the charging time increases, the rate of change of the charging current of the coil decreases exponentially, resulting in too slow charging.

[0037] Based on this, the present application proposes Embodiment 1:

[0038] like Figure 2 As shown, the present application proposes a charging method based on laboratory conditions, that is, immersing the coil in liquid nitrogen in the laboratory:

[0039] S1. When charging is started, the charging current of the high-temperature superconducting non-insulated coil is controlled to rise to a maximum limiting current value at a fixed current rise rate; wherein the maximum limiting current value is greater than the working current value of the high-temperature superconducting non-insulated coil;

[0040] S2. When the charging current rises to the maximum limiting current value, the charging current is suddenly changed to the working current value of the coil and maintained at the working current value.

[0041] In this embodiment, since the coil inductance in the laboratory is small, the inter-turn resistance is large, and the current change rate is large, its heating power is also small. Since the coil is immersed in liquid nitrogen, its cooling power is large. Therefore, the fixed current rise rate can be set to a larger value to improve the charging efficiency of the coil. Any current rise rate corresponding to the maximum heating power of the coil being less than the cooling power that can be provided by liquid nitrogen based on the fixed current rise rate satisfies this embodiment.

[0042] In this embodiment, during the process of reducing the charging current to the working current, the duration is short, the coil inductance in the laboratory is small, the inter-turn resistance is large, and the liquid nitrogen can provide a large cooling power, and the current is reduced at a large reduction rate, and its heat generation power is also small, and the accumulated heat during the reduction process is also small. Therefore, in order to increase the charging rate, the "mutation" in this embodiment can be to mutate the charging current to the working current value of the coil at a reduction rate similar to the fixed increase rate, or to reduce the current at a larger reduction rate, for example, a reduction rate of 10-100A / s. It is sufficient to ensure that the temperature increase is not obvious.

[0043] In this embodiment, the charging current is controlled to rise to above the working current of the coil, and overcurrent charging is performed, so that the charging current of the coil can continue to maintain a linear growth, allowing the charging current of the coil to quickly reach or even exceed the working current, and then the charging current value is reduced to the working current value in the form of a sudden change. At this time, the current on the inter-turn resistance decreases rapidly, and the current quickly becomes almost entirely passed through the coil, which is manifested as a rapid decrease in the coil voltage and a significant reduction in the charging time of the coil.

[0044] Based on the above charging method, the applicant applied the charging curve of the above charging current to actual working conditions and found that the coil charging time was not significantly reduced, and the coil was seriously heated and even burned.

[0045] According to the analysis of the applicant, under laboratory conditions, the coil is immersed in liquid nitrogen, and the cooling power of liquid nitrogen is relatively large. Although the coil generates heat during the current change process, under the condition that the liquid nitrogen directly contacts the coil, the coil temperature rises not significantly, so the superconducting performance of the coil will not change. Therefore, the charging rate can be greatly improved. In actual working conditions, not only the size of the coil increases significantly, resulting in a significant increase in its inductance, but also the turn-to-turn resistance decreases significantly, resulting in great sensitivity to the current change rate. The heating power of the coil during the charging process will become very large. In addition, in actual working conditions, although the working environment temperature of the coil is lower, the cooling power of its refrigeration system is small, and a cold plate is required to transfer the cold to the coil, so the coil will get less cold. When the heating power is larger and the actual cooling power of the coil is smaller, if the charging current is directly reduced to the working current after the maximum current limit is reached, the coil temperature may rise significantly, and the increase in coil temperature will cause the superconducting performance of the coil to decrease. More current enters the turn-to-turn resistance, generating greater heat, forming a vicious circle.

[0046] Specifically, based on the formula: , it can be obtained that I(t)-Isc represents the current on the inter-turn resistance. The resistive heating on the inter-turn resistance will cause the coil to heat up. The heating power of the coil can be calculated by the following formula:

[0047] P = (I (t) - Isc) 2 *Rc

[0048] Among them, P represents the heating power, I(t) represents the charging current, I(t)-Isc represents the current on the inter-turn resistance, Rc represents the inter-turn resistance, and L represents the coil inductance.

[0049] For a coil current that rises at a rising rate k (A / s), that is, I(t)=kt, the coil charging current Isc=kt-kτ(1-e^(-t / τ)), where τ=L / Rc is the time constant. Therefore, the current I on the inter-turn resistance R =kτ(1-e^(-t / τ)), that is, the initial value of the inter-turn current is 0, and as time increases, it increases exponentially until I R =kτ. So the maximum heating power P=k 2 *(L 2 / Rc).

[0050] If the charging curve of the charging method in the above embodiment is used, when the charging current of the coil drops from the maximum limiting current value to the working current value of the coil instantaneously, the current change rate may reach tens or hundreds of A / s. For the above laboratory, the coil is immersed in liquid nitrogen test scenario. When the charging current drops, take k=100A / s as an example. The coil inductance L is 72uH, the turn-to-turn resistance Rc is 2uΩ, and the maximum heating power P is 3.5W. The coil immersed in liquid nitrogen has a liquid nitrogen of several hundred W / m 2 / K cooling power, therefore, for the above laboratory, when the coil is immersed in liquid nitrogen test scenario, the charging current of the coil drops instantaneously from the maximum limiting current value to the working current value of the coil, and the charging curve will not cause the coil to heat up.

[0051] However, in actual working conditions, since the inductance of the coil is larger and the inter-turn resistance is smaller, the maximum heating power formula of the coil is: P=k 2 *(L 2 / Rc), the maximum heating power of the coil will be very large; and, under actual working conditions, the power of the refrigeration system is relatively small. For example, the refrigeration power required to maintain a 20K temperature environment is about 20W. After the cold is transferred to the coil through the cold plate, the refrigeration power obtained by the coil is much less than 20W. In actual working conditions, taking the parameters of a typical large uninsulated coil: inductance L=0.1H, inter-turn resistance Rc=100uΩ as an example, when k=100A / s, the maximum heating power is 1000000W. For the actual working scenarios of large high-temperature superconducting uninsulated coils, the temperature of the coil will rise rapidly, and the rise in coil temperature will cause the superconducting performance of the coil to decrease. More current enters the inter-turn resistance, generating greater heat, forming a vicious cycle, and even burning the coil.

[0052] Based on this, Example 2 is proposed in this application:

[0053] For the coil charging control method under actual working conditions, see Figure 3 As shown, it includes: step S101, when charging starts, controlling the charging current of the high-temperature superconducting non-insulated coil to rise to a flat-top current value at a preset current rise rate; the flat-top current value is greater than the working current value of the high-temperature superconducting non-insulated coil.

[0054] Step S102, controlling the charging current to maintain the flat-top current value within a preset time period.

[0055] Step S103, when the preset time is reached, the charging current is controlled to decrease to the working current value of the high-temperature superconducting non-insulated coil according to the preset current reduction rate. Exemplarily, when charging is started, the charging current of the high-temperature superconducting non-insulated coil is controlled to increase to a flat-top current value at a preset current increase rate; the flat-top current value is greater than the working current value of the high-temperature superconducting non-insulated coil; further, within the preset time, the charging current is controlled to maintain the flat-top current value; finally, when the preset time is reached, the charging current is controlled to decrease to the working current value of the high-temperature superconducting non-insulated coil according to the preset current reduction rate. The charging current of the entire charging process can be expressed by the following formula:

[0056]

[0057] Where I(t) represents the current value of the charging current over time, k represents the preset current increase rate, k1 represents the preset current decrease rate (negative number), I max is the flat-top current value; I op is the working current value; when t belongs to the time interval of (0, t1], the charging current continues to rise to reach the plateau current; when t belongs to the time interval of (t1, t2], the charging current maintains the plateau current; when t belongs to the time interval of (t2, t3], the charging current continues to drop to the working current; after t3, the charging current maintains the working current until the coil is fully charged.

[0058] Based on this, the current flowing through the superconducting tape on the high-temperature superconducting uninsulated coil, that is, the coil charging current Isc is:

[0059]

[0060] Where I(t) represents the current value of the charging current over time, k represents the preset current increase rate, k1 represents the preset current decrease rate (negative number), I max is the flat-top current value; I op is the working current value; when t belongs to the time interval of (0, t1], the charging current continues to rise to reach the plateau current; when t belongs to the time interval of (t1, t2], the charging current maintains the plateau current; when t belongs to the time interval of (t2, t3], the charging current continues to drop to the working current; after t3, the charging current maintains the working current until the coil is fully charged.

[0061] For example, when the coil inductance L = 0.1H and the turn-to-turn resistance Rc = 100uΩ, the following can be obtained: Figure 4 The current and heating power variation diagrams of the second embodiment (the charging current curve of the coil has a flat top time) and the first embodiment (the charging current curve of the coil has no flat top stage) are shown in FIG. Figure 5The coil charging current curve shown has a flat top stage and the coil charging current curve has no flat top stage. Figure 4 In the figure, the horizontal axis represents time in seconds, the left vertical axis represents the current value in A, and the right vertical axis represents the coil heating power in W. Figure 5 In the figure, the horizontal axis represents time, whose unit is s, and the vertical axis represents current, whose unit is A.

[0062] Depend on Figure 4 It can be seen that by controlling the charging current of the high-temperature superconducting uninsulated coil to continue to rise after charging is started until the charging current reaches the plateau current value, the charging current of the high-temperature superconducting uninsulated coil reaches the working current value earlier (about 900 seconds); for the edge coil without a plateau stage, the charging current of the coil reaches the working current value more slowly (greater than 1200 seconds).

[0063] Depend on Figure 4 , Figure 5 As can be seen from Example 1, when the coil is charged, as time increases, the linear term of the coil charging current has an advantage over the exponential term, that is, the coil charging current increases linearly; and when the charging current reaches the plateau current value, as time increases, the coil charging current growth rate decreases exponentially; when using the charging control method that does not include the plateau stage (Example 1), when the charging current reaches the working current value, it enters a stable stage, and the current charging in the loop becomes slower and slower, which takes a long time; when using the charging control method that includes the plateau stage, the coil charging current increases linearly during overcurrent, so that the coil charging current quickly reaches or even exceeds the working current value; even if the inductance of the coil increases and the inter-turn resistance decreases in actual working conditions, the cooling power obtained by the coil is small In this case, due to the existence of the flat-top stage and the current reduction stage at the same time, the process of the charging current decreasing from the flat-top current value to the working current value is equivalent to a relatively long time, the current change rate is very small, and the heating power of the coil is very small. Therefore, the coil temperature hardly changes in this stage, and the superconducting performance of the coil can be maintained, so that more current can flow into the coil more quickly, further improving the charging efficiency of the coil; at the same time, in the current reduction stage, the coil charging current during discharge is rapidly reduced. Due to the existence of inductance, when the charging current changes, the coil charging current changes slowly at first and then quickly. When the charging current is stable, the coil charging current changes more and more slowly. Therefore, the setting of the flat-top stage and the current reduction stage can achieve a reduction in the overall charging time.

[0064] The charging control method of the high-temperature superconducting non-insulated coil provided in the present application controls the charging current of the high-temperature superconducting non-insulated coil to rise to a flat-top current value at a preset rising rate when charging is started; the flat-top current value is greater than the working current value of the high-temperature superconducting non-insulated coil; within a preset time period, the charging current is controlled to maintain the flat-top current value; when the preset time period is reached, the charging current is controlled to decrease to the working current value of the high-temperature superconducting non-insulated coil according to a preset falling rate; the above control method does not need to change the coil structure, does not affect the coil preparation process, and retains the self-protection ability and simple preparation characteristics of the high-temperature superconducting non-insulated coil; and by controlling the charging current to maintain the flat-top current value within the preset time period, the purpose of fast charging of the high-temperature superconducting non-insulated coil can be achieved on the basis of retaining the self-protection ability of the high-temperature superconducting non-insulated coil.

[0065] In Example 1, since the coil is immersed in liquid nitrogen, its refrigeration power is relatively strong. Therefore, in order to reduce the charging time, the current rise rate can be set to be relatively large. However, under actual working conditions, the actual refrigeration power obtained by the coil is relatively small. Therefore, the current rise rate must be controlled to prevent the coil from generating excessive heat power during the current rise process, which affects the superconducting performance and charging of the coil.

[0066] The formula for calculating the heating power of the coil during the current rising stage is: P=k 2 *(L 2 / Rç) where k represents the current change rate, L represents the coil inductance, and Rc represents the turn-to-turn resistance.

[0067] The heating power of the coil is proportional to the square of the current change rate. In order to ensure safety, the current change rate must be limited.

[0068] As an exemplary embodiment, when the charging current is controlled to increase at the preset current rise rate, the actual heating power of the high-temperature superconducting uninsulated coil is less than the preset heating power, and the preset heating power is less than the maximum allowable heating power corresponding to the high-temperature superconducting uninsulated coil.

[0069] In one embodiment, the preset flow rate is less than , wherein Pmax is the maximum allowable heating power of the coil, so that the heating power of the high-temperature superconducting non-insulated coil when working according to the preset current rise rate is less than the maximum allowable heating power corresponding to the high-temperature superconducting non-insulated coil.

[0070] Taking the inductance L=0.1H and the inter-turn resistance Rc=100uΩ as an example, the maximum heating power P=100k 2 , when the current rate k=0.1 A / s, the maximum heating power of the coil P=1W. The maximum heating power allowed for the coil should be less than 1W, or even less than 0.1W.

[0071] In one embodiment, a performance test may be performed on the high-temperature superconducting uninsulated coil to measure the maximum current rise rate corresponding to the high-temperature superconducting uninsulated coil at the maximum heating power, and the preset current rise rate may be further set to a value less than the maximum current rise rate.

[0072] On the other hand, the maximum allowable heating power corresponding to the high-temperature superconducting uninsulated coil is related to the cooling capacity received by the high-temperature superconducting uninsulated coil from the refrigeration system. Therefore, as an exemplary embodiment, the maximum allowable heating power is less than the cooling capacity actually acted on the high-temperature superconducting uninsulated coil by the refrigeration equipment.

[0073] For the current reduction process, the maximum heating power of the coil is proportional to the square of the current change rate. Therefore, the preset current increase rate and the preset current reduction rate are generally consistent, that is, the preset current increase rate and the preset current reduction rate are equal.

[0074] Since the coil flows less current when the charging current drops from the flat-top current value to the operating current value, the absolute value of the preset current increase rate may be greater than the absolute value of the preset current decrease rate; therefore, as an exemplary embodiment, the absolute value of the preset current increase rate may be less than the preset current decrease rate.

[0075] As an exemplary embodiment, the plateau current value is less than 0.8 times of the critical current.

[0076] As mentioned above, the flat-top current value needs to be greater than the working current value; however, the high-temperature superconducting uninsulated coil is at risk of burning when the flat-top process is performed at an excessively large flat-top current value; to solve this problem, in this embodiment, the flat-top current is less than 0.8 times the critical current; wherein the critical current is the maximum current allowed to pass through the high-temperature superconducting uninsulated coil.

[0077] When testing the high-temperature superconducting uninsulated coil, it was found that the high-temperature superconducting uninsulated coil would not be at risk of burning when it was flat-topped at 1.05 times to 1.1 times the operating current value within a preset time; based on this, in one embodiment, the flat-top current value is less than 0.8 times the critical current and less than 1.1 times the operating current.

[0078] In one embodiment, the plateau current value is less than 0.7 times the critical current and less than 1.1 times the operating current.

[0079] In one embodiment, the plateau current value is less than 0.8 times the critical current and less than 1.05 times the operating current.

[0080] In one embodiment, the plateau current value is less than 0.7 times the critical current and less than 1.05 times the operating current.

[0081] In the above embodiment, an optional range of flat-top current values ​​is given. Within this range, the high-temperature superconducting non-insulated coil can be quickly charged by controlling the charging current to maintain the flat-top current value within a preset time. However, different flat-top current values ​​and different preset time periods can affect the charging time of the high-temperature superconducting non-insulated coil during the charging process alone or together. Therefore, it is necessary to select a flat-top current value within the optional range of flat-top current values ​​as the optimal flat-top current value, and determine a preset time period in conjunction with the optimal flat-top current value, so that within the preset time period, controlling the charging current to maintain the flat-top current value can minimize the charging time of the high-temperature superconducting non-insulated coil during the charging process.

[0082] Based on this, as an exemplary embodiment, the method for determining the flat-top current and the preset time length includes: determining a preset rising current rate interval and a preset falling current rate interval based on coil parameters and the maximum allowable heating power; based on the preset rising current rate interval, the preset falling current rate interval and the flat-top current value, selecting the preset flat-top current value with the shortest coil charging time as the optimal flat-top current value; and calculating the preset time length based on the optimal flat-top current value.

[0083] In this embodiment, the preset rising flow rate interval and the preset falling flow rate interval are obtained by calculating the coil parameters under the constraint of the maximum allowable heating power; in one embodiment, the maximum allowable heating power can be used as the constraint value, and the allowable current change rate interval is calculated by the heating power calculation formula represented by the current change rate in the above embodiment as the preset rising flow rate interval and the preset falling flow rate interval.

[0084] Furthermore, based on the interval constraints of the preset rising rate interval, the preset falling rate interval and the flat-top current value, the preset rising rate interval, the preset falling rate interval and the flat-top current value can be traversed respectively to obtain the charging time corresponding to each rising rate in the preset rising rate interval, each falling rate in the preset falling rate interval and each flat-top current value, and further select the preset flat-top current value with the smallest coil charging time as the optimal flat-top current value.

[0085] Furthermore, after the optimal flat-top current value is obtained, the preset time length can be calculated by using a calculation formula for the coil charging current within the preset time length.

[0086] The above embodiment obtains, through calculation, the optimal flat-top current value and preset time length that can minimize the charging time of the high-temperature superconducting uninsulated coil during the charging process; however, the above embodiment has the problem of complex calculation process and large amount of calculation; to solve this problem, as an exemplary embodiment, the preset time length is less than twice the time constant of the high-temperature superconducting uninsulated coil.

[0087] In this embodiment, the time constant of the coil can be calculated by means of coil parameters, and the preset time length can be further set to a value less than twice the time constant of the high temperature superconducting uninsulated coil.

[0088] In one embodiment, the flat-top current value can be selected as any value within the interval greater than the working current value and less than 0.8 times the working current value, and the preset time length can be selected as any value within the interval greater than zero and less than twice the time constant of the high-temperature superconducting uninsulated coil.

[0089] In one embodiment, the flat-top current value can be selected from any value within the interval greater than the working current value and less than 0.7 times the working current value, and the preset time length can be selected from any value within the interval greater than zero and less than twice the time constant of the high-temperature superconducting uninsulated coil.

[0090] In one embodiment, the flat-top current value may be selected as an optimal current value, and the preset time length may be selected as any value within a range greater than zero and less than twice the time constant of the high-temperature superconducting uninsulated coil.

[0091] As an exemplary embodiment, after charging is started, before controlling the charging current of the high-temperature superconducting non-insulated coil to continue to rise, it also includes: after charging is started, after passing a test current into the high-temperature superconducting non-insulated coil, obtaining a test result of the high-temperature superconducting non-insulated coil; when the test result shows that the coil is normal, controlling the charging current of the high-temperature superconducting non-insulated coil to continue to rise.

[0092] In this embodiment, before controlling the charging of the high-temperature superconducting non-insulated coil, the high-temperature superconducting non-insulated coil is tested in advance to check whether the high-temperature superconducting non-insulated coil is working normally; specifically, after charging is started, a test current is passed into the high-temperature superconducting non-insulated coil, and the test result of the high-temperature superconducting non-insulated coil is obtained; when the test result shows that the coil is normal, the charging current of the high-temperature superconducting non-insulated coil is controlled to continue to rise.

[0093] As a specific application example of the present invention, this example provides a charging control method for a high-temperature superconducting non-insulated coil. For example, Figure 6 is a schematic diagram of the current variation over time under a charging control method of a high-temperature superconducting non-insulated coil according to an embodiment of the present invention, Figure 6 In the figure, the horizontal axis is time (s), and the vertical axis is the normalized critical current. Figure 6 As shown, the method includes:

[0094] After charging is started, a test current is passed into the high-temperature superconducting non-insulated coil, and a test result of the high-temperature superconducting non-insulated coil is obtained.

[0095] When the test result shows that the coil is normal, the charging current of the high-temperature superconducting non-insulated coil is controlled to rise to a flat-top current value at a preset current rise rate; wherein the charging current of the high-temperature superconducting non-insulated coil reaches the flat-top current value at 720s, and the flat-top current value is 0.7 times the critical current value;

[0096] Within 720s to 870s, controlling the charging current to maintain the flat-top current value;

[0097] After 870 seconds, the charging current is controlled to continuously decrease according to a preset current reduction rate until the charging current reaches the working current of the high-temperature superconducting non-insulated coil.

[0098] For example, Figure 7 is a schematic diagram of voltage variation over time in a charging control method for a high-temperature superconducting non-insulated coil according to an embodiment of the present invention, Figure 8 is a voltage diagram of a magnetic field changing with time under a charging control method of a high-temperature superconducting non-insulated coil according to an embodiment of the present invention; Figure 7 , Figure 8 In the figure, the curve corresponding to the "normal charging method" represents the change under the traditional charging control method, and the curve corresponding to the "fast charging method" represents the change under the charging control method of this embodiment. The horizontal axis is time, unit (s). Figure 7 The vertical axis is voltage, the unit is (uV), Figure 8 The vertical axis is the magnetic field in (T); see Figure 7 , Figure 8 The charging control method of this embodiment first increases the charging current to a flat-top current higher than the working current of the high-temperature superconducting non-insulated coil, and then reduces the charging current from the flat-top current to the current working point, so that the current in the branch where the inter-turn resistance is located is rapidly reduced and quickly enters the branch where the superconducting resistance is located, so as to achieve the purpose of fast charging of the high-temperature superconducting non-insulated coil; for details, see Figure 7 , Figure 8 , the high-temperature superconducting uninsulated coil quickly reaches the operating current, saving about 1 / 4 of the time.

[0099] An embodiment of the present invention also provides a computer device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus, the memory is used to store a computer program; the processor is used to execute a method in any of the above embodiments by running the computer program stored in the memory.

[0100] Fig. 9 is a structural block diagram of an optional computer device according to an embodiment of the present application, such as Fig. 9As shown, it includes a processor 10, a communication interface 20, a memory 30 and a communication bus 40, wherein the processor 10, the communication interface 20 and the memory 30 communicate with each other through the communication bus 40, wherein:

[0101] A memory 30, for storing computer programs;

[0102] The processor 10 is used to implement the charging control method of the high-temperature superconducting non-insulated coil as described in any of the above embodiments when executing the computer program stored in the memory 30.

[0103] Optionally, in this embodiment, the communication bus may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The communication bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0104] The communication interface is used for communication between the above-mentioned computer device and other devices.

[0105] The memory may include RAM, or may include non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0106] The above-mentioned processor can be a general-purpose processor, which can include but not be limited to: CPU (Central Processing Unit), NP (Network Processor), etc.; it can also be DSP (Digital Signal Processing), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0107] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0108] It can be understood by those skilled in the art that Fig. 9The structure shown is for illustration only. The device for implementing any one of the methods in the above embodiments may be a terminal device, which may be a smart phone (such as an Android phone, an IOS phone, etc.), a tablet computer, a PDA, a mobile Internet device (Mobile Internet Devices, MID), a PAD, or other terminal devices. Fig. 9 It does not limit the structure of the above electronic device. For example, the terminal device may also include Fig. 9 More or fewer components (such as network interfaces, display devices, etc.) shown in, or with Fig. 9 Different configurations shown.

[0109] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing the hardware related to the terminal device through a program, and the program can be stored in a computer-readable storage medium, which can include: a flash drive, ROM, RAM, a magnetic disk or an optical disk, etc.

[0110] As an exemplary embodiment, the present application also provides a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute any one of the method steps of the present embodiment when running.

[0111] Optionally, in this embodiment, the above-mentioned storage medium can be used to execute the program code of the method steps of the embodiment of the present application.

[0112] Optionally, in this embodiment, the storage medium may be located on at least one network device among a plurality of network devices in the network shown in the above embodiment.

[0113] Optionally, in this embodiment, the storage medium is configured to store data for executing the method in the above embodiment.

[0114] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, which will not be described in detail in this embodiment.

[0115] Optionally, in this embodiment, the storage medium may include, but is not limited to, various media that can store program codes, such as a USB flash drive, a ROM, a RAM, a mobile hard disk, a magnetic disk, or an optical disk.

[0116] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0117] If the integrated units in the above embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in the above computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling one or more computer devices (which may be personal computers, servers or network devices, etc.) to execute all or part of the steps of the method in the above embodiments.

[0118] In the several embodiments provided in the present application, it should be understood that the disclosed client can be implemented in other ways. Among them, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution provided in this embodiment.

[0120] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0121] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0122] The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A charging control method for a high-temperature superconducting non-insulated coil, characterized in that: include: When charging is started, the charging current of the high-temperature superconducting non-insulated coil is controlled to increase to a maximum limiting current value at a fixed current rise rate; wherein the maximum limiting current value is greater than the working current value of the high-temperature superconducting non-insulated coil; When the charging current rises to the maximum limiting current value, the charging current is suddenly changed to the working current value of the high-temperature superconducting non-insulated coil and maintained at the working current value, and the fixed current rise rate is an arbitrary current rise rate corresponding to the maximum heating power of the coil being less than the cooling power that can be provided by liquid nitrogen based on the fixed current rise rate; wherein, in the process of suddenly changing the charging current to the working current value of the high-temperature superconducting non-insulated coil, the charging current is reduced to the working current value at a reduction rate greater than or equal to the fixed current rise rate.

2. A charging control method for a high-temperature superconducting non-insulated coil, characterized in that: include: When charging is started, controlling the charging current of the high-temperature superconducting non-insulated coil to rise to a flat-top current value at a preset current rise rate; The flat-top current value is greater than the working current value of the high-temperature superconducting non-insulated coil; Controlling the charging current to maintain the flat-top current value within a preset time period; When the preset time length is reached, the charging current is controlled to drop to the working current value of the high-temperature superconducting uninsulated coil according to the preset current reduction rate, and the flat-top current value is less than 0.8 times the critical current value of the high-temperature superconducting uninsulated coil; the preset time length is less than twice the time constant of the high-temperature superconducting uninsulated coil.

3. The charging control method of the high temperature superconducting non-insulated coil according to claim 2, characterized in that: When the charging current is controlled to increase at the preset current rise rate, the actual heating power of the high-temperature superconducting non-insulated coil is less than the preset heating power.

4. The charging control method of the high temperature superconducting non-insulated coil according to claim 3, characterized in that: The preset heating power is less than or equal to the maximum allowable heating power during the operation of the high-temperature superconducting non-insulated coil, wherein the maximum allowable heating power is less than or equal to the actual cooling capacity of the high-temperature superconducting non-insulated coil provided by the refrigeration equipment during the operation of the high-temperature superconducting non-insulated coil.

5. The charging control method for a high temperature superconducting non-insulated coil according to any one of claims 2 to 4, characterized in that: The preset upflow rate and the preset downflow rate are equal in magnitude.

6. The charging control method of the high temperature superconducting non-insulated coil according to claim 2, characterized in that: The flat-top current value and the preset duration are determined by: Acquiring coil parameters of the high temperature superconducting non-insulated coil, wherein the coil parameters include coil inductance and turn-to-turn resistance; Determine, based on a heat generation power calculation formula during the current change process of the high-temperature superconducting non-insulated coil, a preset rising current rate interval and a preset falling current rate interval corresponding to a heat generation power less than a maximum allowable heat generation power corresponding to the high-temperature superconducting non-insulated coil; An enumeration method is adopted to determine the flat-top current value and the duration of the flat-top current value that can minimize the charging time of the high-temperature superconducting non-insulated coil within the preset rising current rate interval, the preset falling current rate interval and the flat-top current value interval.

7. The charging control method of the high temperature superconducting non-insulated coil according to claim 2, characterized in that: The method further includes: before charging is started, after a test current is passed into the high-temperature superconducting non-insulated coil, obtaining a test result of the high-temperature superconducting non-insulated coil; When the test result shows that the coil is normal, the charging current of the high-temperature superconducting non-insulated coil is controlled to continue to increase.

8. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the charging control method for the high-temperature superconducting uninsulated coil according to any one of claims 1 to 7 by executing the computer instructions.

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