Superconducting magnet excitation system

Abstract

Field charging system for superconducting magnets [Solution] A superconducting circuit for a superconducting magnet includes a first temperature region, a second temperature region, at least one first component, at least one second component, and an excitation system. The first temperature region defines a first temperature, and the second temperature region defines a second temperature, the second temperature being higher than the first temperature. The at least one first component is disposed within the first temperature region. The at least one second component is disposed within the second temperature region. The excitation system includes at least one flexible connection electrically coupling the first component and the second component. The flexible connection allows the first component and the second component to displace and move due to thermal expansion and contraction caused by the different first and second temperatures.

Description

[Technical Field]

[0001] The present disclosure relates to superconducting magnets, and more particularly to excitation systems for superconducting magnets such as those used in superconducting generators. [Background technology]

[0002] Superconducting machines typically contain superconducting magnets, which consist of coils of superconducting circuits. In their superconducting state, the superconducting circuits have no electrical resistance, allowing them to carry much larger currents than ordinary wires and generate stronger magnetic fields. Superconducting magnets can therefore generate larger magnetic fields than non-superconducting electromagnets and are less expensive to operate because energy is not dissipated as heat in the windings. Superconducting magnets are therefore commonly used in magnetic resonance imaging (MRI) machines and scientific instruments such as nuclear magnetic resonance (NMR) spectrometers, generators, mass spectrometers, nuclear fusion reactors, and particle accelerators.

[0003] During operation, the windings of a superconducting magnet must be cooled below their critical temperature (i.e., the temperature at which the winding material changes from a normal resistive state to a superconducting state). Typically, the windings are cooled to a temperature significantly below their critical temperature. This lower temperature allows the superconducting windings to withstand high currents and magnetic fields without reverting to a non-superconducting state. Therefore, liquid or mechanical cooling is commonly used to maintain the windings at a temperature sufficient to maintain their superconducting state. Liquid cooling uses a liquid refrigerant (e.g., helium, hydrogen, or argon, depending on the operating temperature) as the coolant, whose boiling point is much lower than the critical temperature of most winding materials. For example, helium boils at 4.2 Kelvin, significantly lower than the critical temperature of 9 Kelvin for niobium-titanium (NbTi) superconducting wire. Therefore, the superconducting magnet and liquid refrigerant are contained in a thermally insulated vessel called a cryostat. Alternatively, mechanical cooling involves cooling the superconducting magnet using two-stage mechanical refrigeration.

[0004] Furthermore, during operation of a superconducting magnet, when the magnet is energized, the windings can be shorted with a piece of superconducting material. The short circuit is achieved by a switch (sometimes called a persistent switch), which typically represents a piece of superconducting material located inside the superconducting magnet, connected between the winding ends, and attached to a small heater. The windings thus become closed superconducting loops, and a persistent current flows through them for a continuous period, maintaining the magnetic field even when the power is turned off. The advantage of this persistent mode is that the magnetic field stability is superior to that achievable with an optimal power supply and no energy is required to power the windings. For example, superconducting switches are typically bifilar wound to minimize their electrical induction, which, in the superconducting state, has zero resistance and negligible inductance.

[0005] Thus, when the superconducting magnet is first turned on, the switch is heated above its transition temperature, causing it to become resistive. To operate in persistent mode, the supply current is adjusted until the desired magnetic field is achieved, and then the heater is turned off. The persistent switch cools to its superconducting temperature, thereby shorting the winding. The power supply can then be turned off.

[0006] To further assist this system, the various components of the superconducting magnets and switches can be located in separate areas within the superconducting machine to reduce unwanted heat transfer between components designed to be maintained at low or high temperatures. However, displacements and movements between the various components of the superconducting magnets due to thermal expansion and contraction, as well as dynamic load changes due to the magnetic field moving into persistent mode, must also be considered.

[0007] SUMMARY OF THE INVENTION Accordingly, the present disclosure relates to an improved excitation system for superconducting circuits that addresses the aforementioned problems. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2017 / 287608 Summary of the Invention

[0009] Aspects and advantages of the present disclosure will be set forth in part in the description that follows, or will be obvious from the description, or may be learned by practice of the present disclosure.

[0010] In one aspect, the present disclosure relates to a superconducting circuit for a superconducting magnet. The superconducting circuit includes a first temperature region, a second temperature region, at least one first component, at least one second component, and an excitation system. The first temperature region defines a first temperature, and the second temperature region defines a second temperature, the second temperature being higher than the first temperature. The at least one first component is disposed within the first temperature region. The at least one second component is disposed within the second temperature region. The excitation system includes at least one flexible connector electrically coupling the first component and the second component. The flexible connector allows the first component and the second component to displace and move due to thermal expansion and contraction caused by different first and second temperatures.

[0011] In one embodiment, the first component includes a plurality of superconducting coils, the second component includes at least one thermal shield surrounding the plurality of superconducting field coils, and the excitation system is configured to energize the plurality of superconducting coils.

[0012] In another embodiment, the excitation system further includes a plurality of high current leads and a superconducting switch.

[0013] In an additional embodiment, the plurality of high current leads further includes a pair of high temperature superconductor (HTS) leads and a pair of resistance leads, the pair of resistance leads being one or more feed-through power lines that pass through a vacuum vessel and are coupled to the pair of HTS leads via at least one flexible connection, and the pair of HTS leads being coupled to a plurality of superconducting field coils and the superconducting switch.

[0014] In another embodiment, the superconducting switch is mounted on a cold plate that is mechanically and thermally coupled to a support structure for the plurality of superconducting field coils, and the pair of HTS lead wires are fixed to the cold plate.

[0015] In yet another embodiment, the connection between the pair of HTS leads and the pair of resistive leads includes the at least one flexible connection and a thermal plate.

[0016] In another additional embodiment, the pair of resistive leads comprises copper, brass, phosphor bronze, or a combination thereof.

[0017] In other additional embodiments, the first temperature is less than about 10 Kelvin (K) and the second temperature is between about 35K and about 55K.

[0018] In yet another embodiment, the superconducting circuit further includes a third temperature zone defining a third temperature higher than the first temperature and the second temperature, and a third component is disposed within the third temperature zone, the third component being connected to the second component via a second flexible connection of the at least one flexible connection.

[0019] In yet another embodiment, the second component includes a thermal shield having at least one electrical component disposed therein, and the third component includes a vacuum vessel having at least one electrical component disposed therein.

[0020] In another embodiment, the at least one flexible connection comprises a braided wire.

[0021] In another aspect, the present disclosure relates to an excitation system for energizing multiple superconducting coils of a superconducting magnet. The excitation system includes at least one high-temperature superconductor (HTS) lead, a power source, and at least one flexible connection. The HTS lead connects a first temperature and a second temperature, the second temperature being different from the first temperature. The power source is disposed at a third temperature and is for supplying power to the excitation system to energize the multiple superconducting coils. At least one flexible connection is electrically coupled between the at least one HTS lead at the first temperature and the power source at the second temperature. Furthermore, the at least one flexible connection allows components of the excitation system to displace and move due to thermal expansion and contraction caused by the different first and second temperatures.

[0022] In one embodiment, the power supply includes one or more feed-through power lines that penetrate the vacuum vessel and thermal shield of the superconducting magnet.

[0023] In another embodiment, one or more rod members are coupled to the one or more feedthrough power lines and are disposed at least partially within the heat shield.

[0024] In another embodiment, the at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, wherein the at least one first flexible connection is coupled to the one or more rod members and a first portion of at least one thermal plate, and the at least one second flexible connection is coupled to a second portion of the at least one thermal plate and at least one HTS lead wire.

[0025] In yet another embodiment, the excitation system further includes a superconducting switch, wherein the at least one HTS lead and the superconducting switch are coupled to the plurality of superconducting coils.

[0026] In yet another aspect, the present disclosure relates to a method for energizing a plurality of superconducting coils of a superconducting magnet, the method including coupling an excitation system to a plurality of superconducting coils and at least one other component of the superconducting magnet, wherein the plurality of superconducting coils and the at least one other component are maintained at different temperatures, the excitation system including a power source, at least one high-temperature superconductor (HTS) lead, and at least one flexible connection electrically coupled between the power source and the at least one HTS lead. The method further includes providing power to the excitation system with the power source and energizing the plurality of superconducting coils. The at least one flexible connection allows displacement and movement of the excitation system components due to thermal expansion and contraction caused by the different temperatures.

[0027] In another embodiment, the method further includes coupling one or more rod members to the one or more feed-through power lines.

[0028] In yet another embodiment, the at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, the method further including coupling the at least one first flexible connection to the one or more rod members at a first portion of at least one thermal plate, and coupling the at least one second flexible connection to a second portion of the at least one thermal plate and the at least one HTS lead.

[0029] These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and claims. The drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, help to explain the principles of the disclosure. [Brief explanation of the drawings]

[0030] A full and enabling disclosure of this disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in this specification, and in which reference is made to the following figures: [Figure 1] FIG. 1 shows a perspective view of one embodiment of a superconducting magnet according to the present disclosure. [Figure 2] 2 shows a perspective view of one embodiment of the superconducting magnet of FIG. 1, particularly showing the internal components of the superconducting magnet. [Figure 3] 1 shows a perspective view of one embodiment of a superconducting switch for a superconducting magnet according to the present disclosure. [Figure 4] 4 shows a detailed view of the superconducting switch of FIG. 3. [Figure 5] 5 shows a detailed perspective view of the superconducting switch of FIG. 4, particularly showing the superconducting windings and heat conducting members of the superconducting switch thermally coupled to the conductive rods. [Figure 6] 1 shows a detailed perspective view of another embodiment of a superconducting switch according to the present disclosure, particularly showing the superconducting winding and thermally conductive member of the superconducting switch electrically coupled to a tube. [Figure 7] 1 shows a simplified schematic diagram of a superconducting magnet according to the present disclosure; [Figure 8] 1 shows a circuit diagram of one embodiment of an excitation system for a superconducting magnet according to the present disclosure. [Figure 9] 1 shows a schematic diagram of one embodiment of various components of an excitation system for a superconducting magnet according to the present disclosure. [Figure 10] 1 shows a partial perspective view of various components of an excitation system for a superconducting magnet according to the present disclosure; [Figure 11]1 illustrates a flow diagram of one embodiment of a method for energizing multiple superconducting coils of a superconducting magnet according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0031] Next, embodiments of the present disclosure will be described in detail. One or more examples of embodiments are illustrated in the drawings. Each example is provided to explain the disclosure, not to limit it. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the scope of the disclosure. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Therefore, the present disclosure is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0032] In general, the present disclosure relates to a superconducting circuit having a flexible excitation system for a superconducting magnet (e.g., a superconducting generator). In one embodiment, for example, the superconducting circuit can include a first temperature region defining a first temperature and a second temperature region defining a second temperature higher than the first temperature. The superconducting circuit can also include a first component disposed within the first temperature region and a second component disposed within the second temperature region. The excitation system of the superconducting circuit includes a flexible connection electrically coupling the first component and the second component. The flexible connection thus allows the first component and the second component to displace and move due to thermal expansion and contraction caused by the different first and second temperatures. In this manner, the superconducting circuit accounts for temperature differences between regions of the superconducting magnet, thereby reducing the risk of damage to the superconducting magnet.

[0033] Referring to the figures, FIGS. 1-3 show perspective views of one embodiment of a superconducting magnet 10 according to the present disclosure. Such superconducting magnets are useful in a variety of applications, including, but not limited to, magnetic resonance imaging (MRI) machines, NMR spectrometers, power generators (e.g., wind turbine generators, etc.), mass spectrometers, nuclear fusion reactors, particle accelerators, levitation, guidance, propulsion, and the like. In particular, FIG. 1 shows an overall perspective view of one embodiment of a superconducting magnet 10 according to the present disclosure, FIG. 2 shows a transparent perspective view of one embodiment of a superconducting magnet 10 according to the present disclosure, and FIG. 3 shows an interior perspective view of one embodiment of a superconducting magnet 10 according to the present disclosure.

[0034] In particular, as shown in FIG. 2 , superconducting magnet 10 includes an insulated vessel 12, which is commonly referred to as a cryostat. As used herein, a cryostat generally refers to a vessel containing a cryogenic cooling system. Furthermore, as shown in FIG. 3 , the insulated vessel 12 of superconducting magnet 10 includes a superconducting circuit 16, which has one or more superconducting coils 23 within the insulated vessel 12, supported by an internal structure 29. Thus, in such an embodiment, the insulated vessel 12 insulates the superconducting circuit 16 so that the wire can be cooled to near absolute zero (e.g., to 10 Kelvin (K), preferably to 4 K). For example, as shown in FIG. 3 , the insulated vessel 12 can include multiple conduits 21 that carry a liquid cryogen (e.g., helium, hydrogen, argon, or other liquid, depending on the operating temperature) from a tank 15 to the internal structure 29 and / or across the interior walls of the insulated vessel 12. Additionally, in one embodiment, the interior portion of the insulated enclosure 12 may include a vacuum vessel 13 and a heat shield 36 (FIG. 7) that blocks thermal radiation and convection between the external environment and the cold components within the insulated enclosure 12, thereby minimizing radiative heat transfer.

[0035] More specifically, as shown, the superconducting circuit 16 may be arranged in a coil and configured to generate a magnetic field. As particularly shown in FIG. 1, the superconducting magnet 10 further includes a power supply 18 connected to an excitation system 20 for energizing the superconducting circuit 16.

[0036] Therefore, in its superconducting state, the superconducting circuit 16 has no electrical resistance, and therefore can carry much larger currents than ordinary wire and generate stronger magnetic fields. Furthermore, during operation, the superconducting circuit 16 must be cooled below its critical temperature (i.e., the temperature at which the wire material changes from its normal resistive state and becomes superconducting). Typically, the superconducting circuit 16 is cooled to a temperature significantly below its critical temperature because the lower the temperature, the better the superconducting windings perform and the superconducting windings can withstand high currents and magnetic fields without reverting to a non-superconducting state.

[0037] 1-3, the superconducting magnet 10 may further include a cooling system 14 that provides liquid cooling for cooling the superconducting circuit 16. More specifically, as shown, the cooling system 14 may include one or more cooling tanks 15 that contain a cooling medium 17 or coolant (FIG. 3). For example, in one embodiment, the cooling medium 17 may be liquid helium, which has a boiling point of 4.2 Kelvin, well below the critical temperature of the wire material.

[0038] In one mode of operation of superconducting magnet 10, after the magnet is energized, superconducting circuit 16 can be shorted with a piece of superconducting material. In such an embodiment, for example, the shorting can be accomplished by excitation system 20 through superconducting switch 25 (sometimes referred to as a persistent switch). In other words, superconducting switch 25 of excitation system 20 generally represents a piece of superconducting material located within superconducting magnet 10 and connected between the end windings of superconducting circuit 16, with a heater capable of raising the temperature of the piece of superconducting material above the transition temperature of the wire. This is because superconducting switches typically exist in a low-temperature superconducting state, typically bifilar wound to minimize electrical inductance, which implies zero resistance and negligible inductance in the superconducting state.

[0039] 4, a heat exchanger 30 (such as a finned copper heat exchanger) may be provided so that the superconducting switch 25 of the excitation system 20 can be cooled by liquid helium. Thus, when the heat exchanger 30 is turned off and the superconducting switch 25 of the excitation system 20 is cooled below its transition temperature, the superconducting circuit 16 becomes a closed superconducting loop, so the power supply 18 can be turned off and a persistent current will flow and the magnetic field will be maintained for a long period of time. The advantage of this sustained mode is therefore that the stability of the magnetic field is better than that achievable with the best power supplies and no energy is required to power the windings.

[0040] Furthermore, when the superconducting magnet 10 is first turned on, the superconducting switch 25 of the excitation system 20 is heated above its transition temperature, causing the superconducting switch 25 of the excitation system 20 to become resistive. To achieve this state, the power supply 18 is connected to a pair of current leads electrically coupled to the superconducting coil 23 and the excitation system 20. The current leads further include at least one resistive current lead and another high-temperature superconductor (HTS) current lead. The supplied current is adjusted until the desired magnetic field is obtained, after which the heater is turned off. The superconducting switch 25 of the excitation system 20 cools to its superconducting temperature, thereby shorting the superconducting circuit 16. The power supply 18 can then be turned off.

[0041] 4-6, the superconducting switch 25 of the excitation system 20 includes a superconducting winding 22 and a heat-conducting member 24. For example, in one embodiment, the superconducting winding may be a bifilar-wound superconducting winding to achieve minimum inductance. Furthermore, in one embodiment, the heat-conducting member 24 includes a first end 26 thermally coupled to the superconducting winding 22 and a second end 28 thermally coupled to the cooling tank 15. For example, as shown in FIG. 4, a heat exchanger 30 may be mounted within the cooling tank 15, and the heat exchanger 30 may be thermally connected to the excitation system 20 by a heat-conducting rod 32 (e.g., a copper rod) fixed to the tank wall 19 ( FIG. 3 ) of the cooling tank 15 by, for example, brazing. Furthermore, as shown in FIGS. 4 and 5, an additional support structure 34 may be attached to the heat-conducting rod 32 by, for example, soldering, and the second end 28 of the heat-conducting member 24 may be fixed to the additional support structure 34. 6, the thermally conductive member 24 may be attached to one of the conduits 21. In such an embodiment, the thermally conductive member 24 may be attached to the conduit 21 using one or more braided copper straps, which may be secured to the thermally conductive member 24 and the conduit 21.

[0042] Referring to FIG. 7 , a simplified schematic diagram of a superconducting magnet 10 is shown. More specifically, as shown, the superconducting magnet 10 generally includes a cooling system 14, a vacuum vessel 13, a cold mass 38, a thermal shield 36 between the cold mass 38 and the vacuum vessel 13, and a cryocooler 40. Furthermore, as shown, the cooling system 14 may generally be disposed relative to the thermal shield 36 of the superconducting magnet 10. In such an embodiment, for example, the cold mass 38 may be a stationary component (e.g., a field winding assembly within which the armature winding assembly rotates). Further, by way of example, the vacuum vessel 13 may be a non-rotating component that supports the field winding assembly. Thus, in such an embodiment, the rotatable components may be disposed to rotate relative to the non-rotatable components during operation of the superconducting magnet 10. In such an embodiment, the thermal shield 36 surrounds the cold mass 38 and shields and / or blocks radiation (indicated by arrows 42) from the vacuum vessel 13. Additionally, as shown, heat is transferred to the cryocooler 40 by the thermal bus / bus bar 44, which blocks most of the radiant heat from the cold mass 38. Additionally, as shown, the thermal bus / bus bar 44 in this configuration is attached to the top of the heat shield 36 for connection to the cryocooler 40. The heat shield 36 also blocks heat conducted through structural components.

[0043] 8-10, various views of components of an excitation system 100 for energizing the superconducting coils of a superconducting magnet 10 as described herein are shown. In particular, FIG. 8 shows one embodiment of a circuit diagram 102 of an excitation system 100 in accordance with the present disclosure. FIG. 9 shows a schematic diagram of one embodiment of various components of an excitation system 100 in accordance with the present disclosure, particularly illustrating how the excitation system 100 penetrates the thermal shield 36 and the vacuum vessel 13 and is coupled between the superconducting coils 23 and the power supply 18. FIG. 10 shows a partial perspective view of various components of an excitation system 100 in accordance with the present disclosure.

[0044] As shown particularly in FIG. 8, the circuit diagram 102 generally includes a power supply 18 that provides power to the excitation system 100 to energize the superconducting coil 23 (FIG. 9) similar to the superconducting coil 23 shown in FIG. 3. Additionally, as shown in FIGS. 8-10, the excitation system 100 further includes a plurality of high current leads 104, a cold mass 38 that includes a superconducting switch assembly 106, and at least one flexible connection 108, 110. More specifically, as shown, the superconducting switch assembly 106 may generally include a superconducting switch 112 and a plurality of electrical protection diodes 114. The superconducting switch assembly 106 is electrically connected in parallel with the inductor that represents the superconducting coil 23.

[0045] 8 and 9, the high current leads 104 described herein can include several types of leads, such as one or more resistive leads 118 and / or one or more HTS leads 120. In other embodiments, as particularly shown in FIG. 10, the resistive leads 118 are vacuum feedthrough power lines, and the resistive leads 118 can further include one or more power connectors 119 coupled to the power source 18 (FIG. 8), one or more conductive rods 121 that penetrate the heat shield 36 and / or the vacuum vessel 13, and / or one or more couplings 123 that secure the power connectors 119 to the conductive rods 121. Furthermore, in one embodiment, as shown in FIG. 10, the superconducting switch 112 and the HTS leads 120 can be mounted to a cold plate 125 that is mechanically and thermally coupled to a support structure (not shown in FIG. 10, but shown in FIGS. 8 and 9) for the plurality of superconducting field coils 23.

[0046] Thus, in one embodiment, components of excitation system 100 are configured to interface with multiple components of superconducting magnet 10, allowing various components of the superconducting magnet to be located in different regions having different temperatures. For example, as particularly shown in FIG. 8 , superconducting switch assembly 106 can be located in a first region (shown below dotted line 122) maintained at a first temperature. The first temperature region can have a temperature below approximately 10 Kelvin (K), such as below approximately 8 K, below approximately 5 K, etc. Furthermore, as shown, at least one hot end of HTS lead 120 can be located in a second region (shown between dotted lines 117 and 122) maintained at a different, second temperature. The cold end of HTS lead 120 can be connected to the first temperature region. In such an embodiment, the second temperature region can have a higher temperature than the first region. For example, the second temperature region can have a temperature in a range of about 20 K to about 70 K (e.g., between about 25 K and about 65 K, between about 30 K and about 60 K, between about 35 K and about 55 K, etc.). Additionally, the power source 18 and / or one or more resistive leads 118 can be located in a third region (shown above dotted line 117) maintained at a third temperature. In certain embodiments, the third temperature region can be at a temperature higher than both the temperatures of the first and second temperature regions. For example, the third temperature region can be at a temperature close to the ambient operating temperature (e.g., greater than 200 K, greater than about 250 K, greater than about 300 K, etc.).

[0047] Thus, the flexible connections 108, 110 can be provided to allow displacement and movement of the components of the excitation system 100 due to thermal expansion and contraction caused by the different temperatures in the first, second, and third temperature zones. Thus, as shown particularly in FIG. 9 , one or more pairs of flexible connections 108, 110 can be electrically coupled between the superconducting coil 23 and the power supply 18 and / or HTS leads 120.

[0048] In one embodiment, for example, the flexible connections 108, 110 may include a first pair of flexible connections 108 and a second pair of flexible connections 110. Furthermore, in one embodiment, the flexible connections 108, 110 described herein may be one or more braided wires or foil members. Furthermore, as shown in FIG. 9 , the excitation system 100 may also include one or more thermal plates 124 (e.g., pairs of thermal plates) coupled between the first pair 108 and the second pair 110 of flexible connections. For example, the first pair of flexible connections 108 may be located at one position or end of the one or more thermal plates 124, and the second pair of flexible connections 110 may be located at another position or end of the one or more thermal plates 124.

[0049] In one embodiment, the first temperature zone refers to where the cold mass (or superconducting coil 23) is located. In the same embodiment, the second temperature zone refers to where the heat shield 36 is located. In that case, the HTS lead 120 can be secured to the heat shield 36 in the second temperature zone. Furthermore, in the same embodiment, the third temperature zone refers to where the vacuum vessel 13 is located. Furthermore, in the same embodiment, one or more thermal plates 124 can be thermally secured to the second temperature zone to maintain the hot end of the HTS lead 120 at the second temperature.

[0050] In other embodiments, the HTS leads 120 described herein can be formed from a superconducting material, such as ceramic, bismuth strontium calcium copper oxide (BSCCO), or yttrium barium copper oxide (YBCO). Additionally, in one embodiment, the resistive leads 118 can be formed from copper, brass, phosphor bronze, or any combination of these materials.

[0051] Referring now to FIG. 11 , a flow diagram of one embodiment of a method 200 for energizing multiple superconducting coils of a superconducting magnet according to the present disclosure is shown. Generally, the method 200 is described herein with reference to the superconducting magnet 10, superconducting circuit 16, and / or excitation system 100 described above with reference to FIGS. 1-10 . However, one skilled in the art will appreciate that the disclosed method 200 may generally be utilized with any superconducting magnet having a suitable configuration. Furthermore, while FIG. 11 depicts steps performed in a particular order for purposes of illustration and explanation, the methods described herein are not limited to any particular order or combination. Using the disclosure provided herein, one skilled in the art will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and / or modified in various ways without departing from the scope of the present disclosure.

[0052] As shown at 202, method 200 includes coupling an excitation system to a plurality of superconducting coils and at least one other component of a superconducting magnet. Further, in one embodiment, the plurality of superconducting coils and the other component are maintained at different temperatures. As further described herein, the excitation system includes a power source, at least one HTS lead, and at least one flexible connection electrically coupled between the power source and the at least one HTS lead. Thus, as shown at 204, method 200 includes supplying power to the excitation system by the power source to energize the plurality of superconducting coils. Thus, by energizing the plurality of superconducting coils in this manner, the flexible connection allows the components of the excitation system to displace and move due to thermal expansion and contraction caused by the different temperatures.

[0053] Various aspects and embodiments of the invention are defined below. [Embodiment 1] A superconducting circuit for a superconducting magnet, the superconducting circuit comprising: a first temperature region defining a first temperature; a second temperature region defining a second temperature, the second temperature being higher than the first temperature; at least one first component disposed within the first temperature region; at least one second component disposed within the second temperature zone; and 1. An excitation system comprising: at least one flexible connection electrically coupling the first component and the second component; The flexible connection allows the first and second components to displace and move due to thermal expansion and contraction caused by different first and second temperatures. Excitation System A superconducting circuit comprising: [Embodiment 2] 2. The superconducting circuit of embodiment 1, wherein the first component includes a plurality of superconducting coils, the second component includes at least one thermal shield surrounding the plurality of superconducting field coils, and the excitation system is configured to energize the plurality of superconducting coils. [Embodiment 3] 3. The superconducting circuit of claim 2, wherein the excitation system further comprises a plurality of high current leads and a superconducting switch. [Embodiment 4] 4. The superconducting circuit of claim 3, wherein the plurality of high current leads further comprises a pair of high temperature superconductor (HTS) leads and a pair of resistance leads, the pair of resistance leads being one or more feed-through power lines that pass through a vacuum vessel and are coupled to the pair of HTS leads via at least one flexible connection, and the pair of HTS leads are coupled to a plurality of superconducting field coils and the superconducting switch. [Embodiment 5] the superconducting switch is installed on a cold plate that is mechanically and thermally coupled to a support structure for the plurality of superconducting field coils; 5. The superconducting circuit of claim 4, wherein the pair of HTS lead wires are fixed to the cold plate. [Embodiment 6] 6. The superconducting circuit according to claim 4 or 5, wherein the connection between the pair of HTS lead wires and the pair of resistance lead wires includes the at least one flexible connection and a heat plate. [Embodiment 7] 7. The superconducting circuit according to any one of embodiments 4 to 6, wherein the pair of resistance leads comprises copper, brass, phosphor bronze, or a combination thereof. [Embodiment 8] The superconducting circuit according to any one of embodiments 1 to 7, wherein the first temperature is lower than about 10 Kelvin (K) and the second temperature is between about 35K and about 55K. [Embodiment 9] A superconducting circuit according to any one of embodiments 1 to 8, further comprising a third temperature region defining a third temperature higher than the first temperature and the second temperature, wherein a third component is disposed within the third temperature region, and the third component is connected to the second component via a second flexible connection part of the at least one flexible connection part. [Embodiment 10] 10. The superconducting circuit of claim 9, wherein the second component includes a thermal shield in which at least one electrical component is disposed, and the third component includes a vacuum vessel in which at least one electrical component is disposed. [Embodiment 11] 11. The superconducting circuit according to any one of embodiments 1 to 10, wherein the at least one flexible connection comprises a braided wire. [Embodiment 12] 1. An excitation system for energizing a plurality of superconducting coils of a superconducting magnet, the excitation system comprising: at least one high temperature superconductor (HTS) lead connecting a first temperature and a second temperature, the second temperature being a different temperature than the first temperature; a power supply located at another third temperature for providing power to the excitation system to energize the plurality of superconducting coils; and at least one flexible connection electrically coupled between the at least one HTS lead at the first temperature and the power source at the second temperature; An excitation system, wherein the at least one flexible connection allows components of the excitation system to displace and move due to thermal expansion and contraction caused by different first and second temperatures. [Embodiment 13] 13. The excitation system of embodiment 12, wherein the power source includes one or more feed-through power lines that penetrate the vacuum vessel and thermal shield of the superconducting magnet. [Embodiment 14] An excitation system as described in embodiment 13, further comprising one or more rod members coupled to the one or more feed-through power lines and at least partially disposed within the heat shield. [Embodiment 15] 15. The excitation system of embodiment 14, wherein the at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, the at least one first flexible connection being coupled to the one or more rod members and a first portion of at least one thermal plate, and the at least one second flexible connection being coupled to a second portion of the at least one thermal plate and at least one HTS lead wire. [Embodiment 16] 16. The excitation system according to any one of embodiments 12 to 15, further comprising a superconducting switch, wherein the at least one HTS lead and the superconducting switch are coupled to the plurality of superconducting coils. [Embodiment 17] 1. A method for energizing a plurality of superconducting coils of a superconducting magnet, the method comprising: coupling an excitation system to a plurality of superconducting coils and at least one other component of the superconducting magnet, the plurality of superconducting coils and the at least one other component being maintained at different temperatures, the excitation system including a power source, at least one high temperature superconductor (HTS) lead, and at least one flexible connection electrically coupled between the power source and the at least one HTS lead; supplying power to the excitation system by the power supply and energizing the plurality of superconducting coils; Including, The method, wherein the at least one flexible connection allows displacement and movement of components of the excitation system due to thermal expansion and contraction caused by different temperatures. [Embodiment 18] 18. The method of embodiment 17, wherein the power supply includes one or more feed-through power lines that penetrate a vacuum vessel and a thermal shield of the superconducting magnet. [Embodiment 19] 19. The method of embodiment 18, further comprising coupling one or more rod members to the one or more feed-through power lines. [Embodiment 20] The at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, and the method includes: coupling the at least one first flexible connection to the one or more rod members at a first portion of the at least one thermal plate; and coupling the at least one second flexible connection to the at least one second portion of the thermal plate and to the at least one HTS lead; 20. The method of embodiment 19, further comprising:

[0054] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any methods incorporated therein. The patentable scope of the disclosure is defined in the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ in material way from the literal language of the claims. [Explanation of symbols]

[0055] 10 Superconducting magnet 12 Insulated container 13 Vacuum container 14 Cooling System 15 Cooling Tank 16 Superconducting Circuits 17 Cooling medium 18 Power supply 19 Tank wall 20 Excitation System 21 Conduit 22 Superconducting winding 23 Superconducting coil 23 Superconducting field coil 24 Thermal Conductive Materials 25 Superconducting Switch 26 First end 28 Second end 29 Internal structure 30 heat exchanger 32 Thermally conductive rod 34 Support structure 36 Heat Shield 38 Cold Mass 40 Cryocooler 44 Busbar 100 Excitation System 104 Current Lead 106 Superconducting Switch Assembly 108 Flexible Connection 112 Superconducting Switch 114 Electrical Protection Diode 118 Resistor Leads 119 Power Connector 120 HTS lead wire 121 Conductive Rod 122 dotted line 123 Coupling 124 Heat Plate 125 Cold Plate 200 ways

Claims

1. A superconducting circuit for a superconducting magnet, the superconducting circuit comprising: a first temperature region defining a first temperature; a second temperature region defining a second temperature, the second temperature being higher than the first temperature; at least one first component disposed within the first temperature region; at least one second component disposed within the second temperature region; and 1. An excitation system comprising: at least one flexible connection electrically coupling the first component and the second component; The flexible connection allows the first and second components to displace and move due to thermal expansion and contraction caused by different first and second temperatures. Excitation System A superconducting circuit comprising:

2. 10. The superconducting circuit of claim 1, wherein the first component includes a plurality of superconducting coils, the second component includes at least one heat shield surrounding the plurality of superconducting field coils, and the excitation system is configured to energize the plurality of superconducting coils.

3. The superconducting circuit of claim 2 , wherein the excitation system further comprises a plurality of high current leads and a superconducting switch.

4. 4. The superconducting circuit of claim 3, wherein the plurality of high current leads further comprises a pair of high temperature superconductor (HTS) leads and a pair of resistance leads, the pair of resistance leads being one or more feed-through power lines that pass through a vacuum vessel and are coupled to the pair of HTS leads via at least one flexible connection, and the pair of HTS leads are coupled to a plurality of superconducting field coils and the superconducting switch.

5. the superconducting switch is installed on a cold plate that is mechanically and thermally coupled to a support structure for the plurality of superconducting field coils; The superconducting circuit of claim 4 , wherein the pair of HTS leads are fixed to the cold plate.

6. The superconducting circuit of claim 4 , wherein a connection between the pair of HTS leads and the pair of resistive leads includes the at least one flexible connection and a thermal plate.

7. The superconducting circuit of claim 4 , wherein the pair of resistive leads comprises copper, brass, phosphor bronze, or a combination thereof.

8. 2. The superconducting circuit of claim 1, wherein the first temperature is less than about 10 Kelvin (K) and the second temperature is between about 35K and about 55K.

9. 2. The superconducting circuit of claim 1, further comprising a third temperature region defining a third temperature higher than the first temperature and the second temperature, wherein a third component is disposed within the third temperature region, and the third component is connected to the second component via a second flexible connection of the at least one flexible connection.

10. 10. The superconducting circuit of claim 9, wherein the second component comprises a thermal shield in which at least one electrical component is disposed, and the third component comprises a vacuum vessel in which at least one electrical component is disposed.

11. The superconducting circuit of claim 1 , wherein the at least one flexible connection comprises a braided wire.

12. 1. An excitation system for energizing a plurality of superconducting coils of a superconducting magnet, the excitation system comprising: at least one high temperature superconductor (HTS) lead connecting a first temperature and a second temperature, the second temperature being a different temperature than the first temperature; a power supply located at another third temperature for providing power to the excitation system to energize the plurality of superconducting coils; and at least one flexible connection electrically coupled between the at least one HTS lead at the first temperature and the power source at the second temperature; An excitation system, wherein the at least one flexible connection allows components of the excitation system to displace and move due to thermal expansion and contraction caused by different first and second temperatures.

13. 13. The excitation system of claim 12, wherein the power source includes one or more feedthrough power lines that penetrate a vacuum vessel and a heat shield of the superconducting magnet.

14. The excitation system of claim 13 , further comprising one or more rod members coupled to the one or more feedthrough power lines and disposed at least partially within the heat shield.

15. 15. The excitation system of claim 14, wherein the at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, the at least one first flexible connection coupled to the one or more rod members and a first portion of at least one thermal plate, and the at least one second flexible connection coupled to a second portion of the at least one thermal plate and at least one HTS lead wire.

16. The excitation system of claim 12 further comprising a superconducting switch, wherein the at least one HTS lead and the superconducting switch are coupled to the plurality of superconducting coils.

17. 1. A method for energizing a plurality of superconducting coils of a superconducting magnet, the method comprising: coupling an excitation system to a plurality of superconducting coils and at least one other component of the superconducting magnet, the plurality of superconducting coils and the at least one other component being maintained at different temperatures, the excitation system including a power source, at least one high temperature superconductor (HTS) lead, and at least one flexible connection electrically coupled between the power source and the at least one HTS lead; supplying power to the excitation system by the power supply and energizing the plurality of superconducting coils; Including, The method, wherein the at least one flexible connection allows displacement and movement of components of the excitation system due to thermal expansion and contraction caused by different temperatures.

18. 18. The method of claim 17, wherein the power source includes one or more feedthrough power lines that penetrate a vacuum vessel and a heat shield of the superconducting magnet.

19. The method of claim 18 , further comprising coupling one or more rod members to the one or more feed-through power lines.

20. The at least one flexible connection includes at least one first flexible connection and at least one second flexible connection, and the method further comprises: coupling the at least one first flexible connection to the one or more rod members at a first portion of the at least one thermal plate; and coupling the at least one second flexible connection to a second portion of the at least one thermal plate and to the at least one HTS lead; 20. The method of claim 19 further comprising:

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