Superconducting device cooling device and method for operating superconducting device cooling device

Abstract

This superconducting device cooling device is provided with: a cryogenic refrigerator (10) for cooling a superconducting device; an interface (110) configured to receive a selection of a plurality of performance parameters of the cryogenic refrigerator (10) by a user and generate an operation mode setting (S1) indicating the selected plurality of performance parameters; and a controller (120) configured to receive the operation mode setting (S1) from the interface (110) and control a plurality of operation parameters of the cryogenic refrigerator (10) that affect the selected plurality of performance parameters.

Description

Technical Field

[0001] The invention relates to a superconducting equipment cooling device and an operating method of the superconducting equipment cooling device. Background Art

[0002] In order to exhibit superconductivity, superconducting devices such as superconducting coils need to be cooled to ultra-low temperatures. Ultra-low temperature refrigerators are often used for ultra-low temperature cooling of superconducting devices.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-052225 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] Existing superconducting device cooling devices are typically designed to operate under predetermined operating conditions set by their manufacturers. Therefore, users of superconducting devices do not have much room to adjust the operating conditions of the superconducting device cooling devices based on their own judgment.

[0008] One of the exemplary purposes of an embodiment of the present invention is to improve the usability of a superconducting device cooling apparatus.

[0009] Means for solving technical problems

[0010] According to one embodiment of the present invention, a superconducting device cooling apparatus comprises: an ultra-low temperature refrigerator for cooling a superconducting device; an interface configured to accept a user's selection of a plurality of performance parameters of the ultra-low temperature refrigerator and generate an operating mode setting representing the selected plurality of performance parameters; and a controller configured to receive the operating mode setting from the interface and control a plurality of operating parameters of the ultra-low temperature refrigerator that affect the selected plurality of performance parameters.

[0011] According to one embodiment of the present invention, a method for operating a superconducting device cooling device is provided. The superconducting device cooling device is provided with a cryogenic refrigerator for cooling the superconducting device. The method comprises the following steps: accepting a user's selection of multiple performance parameters of the cryogenic refrigerator; and controlling multiple operating parameters of the cryogenic refrigerator that affect the selected multiple performance parameters.

[0012] Effects of the Invention

[0013] According to the present invention, the usability of a superconducting device cooling apparatus can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram schematically showing a superconducting magnet device according to an embodiment.

[0015] Figure 2 It is a diagram schematically showing a cryogenic refrigerator according to an embodiment.

[0016] Figure 3 It is a diagram schematically showing a cryogenic refrigerator according to an embodiment.

[0017] Figure 4 This is a flowchart showing an example of an operating method of the superconducting device cooling apparatus according to the embodiment.

[0018] Figure 5 This is a flowchart showing an example of a control algorithm used in the operating method of the superconducting device cooling apparatus according to the embodiment.

[0019] Figure 6 (a) and (b) are graphs showing the operation frequency dependence of the first-stage temperature and the second-stage temperature of the cryogenic refrigerator, respectively. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, identical or equivalent components, parts and processes are marked with the same symbols, and repeated descriptions are appropriately omitted. In each of the drawings, for the convenience of description, the scale or shape of each part is appropriately set, and unless otherwise specifically stated, it is not interpreted as limiting. The embodiments are examples and do not limit the scope of the present invention in any way. All features or combinations thereof described in the embodiments may not necessarily be essential to the invention.

[0021] Figure 1 1 is a diagram schematically showing a superconducting device (e.g., superconducting magnet device 100) according to an embodiment. Superconducting magnet device 100 is mounted on a high magnetic field utilizing device as a magnetic field source of, for example, a single crystal pulling device, an NMR (Nuclear Magnetic Resonance) system, an MRI (Magnetic Resonance Imaging) system, an accelerator such as a cyclotron, a high energy physics system such as a nuclear fusion system, or other high magnetic field utilizing device (not shown), thereby generating a high magnetic field required by the device.

[0022] The superconducting magnet device 100 includes a cryogenic refrigerator 10, a superconducting coil 102, a vacuum container 104, a radiation shield 106, and a magnetic shield 108. For an exemplary structure of the cryogenic refrigerator 10, refer to Figure 2 and Figure 3 This will be described later.

[0023] The superconducting coil 102 is arranged in a vacuum container 104. The superconducting coil 102 is thermally connected to a cryogenic refrigerator 10 provided in the vacuum container 104, and is used in a state of being cooled to a super-low temperature below the superconducting transition temperature. In this embodiment, the superconducting magnet device 100 is configured as a so-called conduction cooling type in which the superconducting coil 102 is directly cooled by the cryogenic refrigerator 10.

[0024] In another embodiment, the superconducting magnet device 100 may be configured by an immersion cooling type in which the superconducting coil 102 is immersed in a cryogenic liquid refrigerant such as liquid helium. In this case, the cryogenic refrigerator 10 is used for cooling (i.e., recondensing) the liquid refrigerant. The cryogenic refrigerator 10 can cool the superconducting coil 102 via the liquid refrigerant.

[0025] The vacuum container 104 is an insulated vacuum container that provides an ultra-low temperature vacuum environment suitable for setting the superconducting coil 102 to a superconducting state, and is also called a cryostat. Typically, the vacuum container 104 has a cylindrical shape or a cylindrical shape with a hollow portion in the center. Therefore, the vacuum container 104 has a substantially flat circular or annular top plate 104a and a bottom plate 104b, and a cylindrical side wall (a cylindrical outer peripheral wall or a coaxially arranged cylindrical outer peripheral wall and an inner peripheral wall) connecting the top plate 104a and the bottom plate 104b. The ultra-low temperature refrigerator 10 can be arranged on the top plate 104a of the vacuum container 104. The vacuum container 104 is made of, for example, a metal material such as stainless steel or other suitable high-strength material, so as to withstand the surrounding pressure (for example, atmospheric pressure).

[0026] The radiation shield 106 is arranged in the vacuum container 104 and is arranged to surround the superconducting coil 102. The radiation shield 106 has a top plate 106a and a bottom plate 106b respectively opposed to the top plate 104a and the bottom plate 104b of the vacuum container 104. The top plate 106a and the bottom plate 106b of the radiation shield 106 also have a substantially flat circular or annular shape, similar to the vacuum container 104. In addition, the radiation shield 106 has a cylindrical side wall (cylindrical outer peripheral wall or coaxially arranged cylindrical outer peripheral wall and inner peripheral wall) connecting the top plate 106a and the bottom plate 106b. The radiation shield 106 is made of, for example, pure copper (for example, oxygen-free copper, tough copper, etc.) or other high thermal conductivity metals. The radiation shield 106 shields the radiation heat from the vacuum container 104 , thereby thermally protecting low-temperature parts such as the superconducting coil 102 , which are arranged inside the radiation shield 106 and cooled to a temperature lower than that of the radiation shield 106 , from the radiation heat.

[0027] In order to suppress the magnetic field generated by the superconducting coil 102 from leaking to the outside, the magnetic shield 108 covers the top plate 104a, the bottom plate 104b and the cylindrical side wall (at least the outer peripheral wall) connecting them of the vacuum container 104. The magnetic shield 108 is made of a magnetic material such as iron, for example. In this embodiment, the magnetic shield 108 is provided separately from the vacuum container 104 and is fixed to the outside of the vacuum container 104. However, in another embodiment, at least a portion of the magnetic shield 108 may be integrated with the vacuum container 104. For example, at least a portion of the top plate 104a, the bottom plate 104b and the side wall connecting them of the vacuum container 104 may be formed of a magnetic material so that it functions as the magnetic shield 108.

[0028] The first cooling stage 33 of the cryogenic refrigerator 10 is thermally connected to the top plate 106a of the radiation shield 106, and the second cooling stage 35 of the cryogenic refrigerator 10 is thermally connected to the superconducting coil 102 inside the radiation shield 106. During the operation of the superconducting magnet device 100, the radiation shield 106 is cooled to a first cooling temperature (for example, 30K to 70K) by the first cooling stage 33 of the cryogenic refrigerator 10, and the superconducting coil 102 is cooled to a second cooling temperature lower than the first cooling temperature (for example, a temperature lower than 10K (for example, about 1K to about 4K)) by the second cooling stage 35 of the cryogenic refrigerator 10. In this way, by supplying power to the superconducting coil 102 cooled to a very low temperature from a coil power supply (not shown) arranged outside the vacuum container 104, a desired high magnetic field can be generated.

[0029] Figure 2 and Figure 3 It is a diagram schematically showing a cryogenic refrigerator 10 according to the embodiment. Figure 2 FIG. 4 shows the appearance of the ultra-low temperature refrigerator 10. Figure 3 2 shows the internal structure of the cryogenic refrigerator 10. As an example, the cryogenic refrigerator 10 is a two-stage Gifford-McMahon (GM) refrigerator.

[0030] The cryogenic refrigerator 10 includes a compressor 12 and an expander 14. The details will be described later. Figure 2 As shown, an interface 110 and a controller 120 are also provided, which together with the cryogenic refrigerator 10 constitute the superconducting device cooling apparatus involved in the embodiment.

[0031] The compressor 12 is configured to recover the working gas of the cryogenic refrigerator 10 from the expander 14, increase the pressure of the recovered working gas, and then supply the working gas again to the expander 14. The working gas is also called refrigerant gas, and is generally helium, but other appropriate gases may be used.

[0032] In addition, usually, the pressure of the working gas supplied from the compressor 12 to the expander 14 and the pressure of the working gas recovered from the expander 14 to the compressor 12 are much higher than the atmospheric pressure, and thus can be referred to as the first high pressure and the second high pressure, respectively. For ease of explanation, the first high pressure and the second high pressure are referred to as high pressure and low pressure, respectively. Typically, the high pressure is, for example, 2 to 3 MPa. The low pressure is, for example, 0.5 to 1.5 MPa, for example, about 0.8 MPa. For ease of understanding, the flow direction of the working gas is indicated by an arrow.

[0033] The compressor 12 includes a compressor body 22 and a compressor housing 23 that accommodates the compressor body 22. The compressor 12 is also referred to as a compressor unit.

[0034] The compressor body 22 is configured to compress the working gas sucked from its suction port and discharge it from the discharge port. The compressor body 22 may be, for example, a vortex pump, a rotary pump, or other pump that increases the pressure of the working gas. The compressor body 22 may also be configured to discharge a constant flow rate of the working gas. Alternatively, the compressor body 22 may also be configured to make the discharged working gas flow rate variable. The compressor body 22 is sometimes also referred to as a compression chamber.

[0035] Furthermore, the compressor 12 includes a compressor motor 24 and a compressor inverter 25 for controlling the operating frequency (i.e., rotation speed) of the compressor motor 24 according to a compressor control signal C1 from a controller 120. The compressor motor 24 is a driving source for driving the compressor body 22, for example, an electric motor driven by three-phase AC power. The compressor inverter 25 is configured to convert the AC power input from a power supply 46 to the compressor inverter 25 into an AC power having a frequency different therefrom, and to supply the converted AC power to the compressor motor 24. The power supply 46 may be an external power supply such as a commercial power supply (three-phase AC power supply). The operating frequency of the compressor motor 24 may be controlled by the compressor inverter 25 within a range of 30 Hz to 100 Hz or within a range of 40 Hz to 70 Hz.

[0036] In order to measure the power consumption of the compressor motor 24, a first measuring instrument 50 may be provided. The first measuring instrument 50 may be provided on a power supply wiring connecting the compressor inverter 25 to the compressor motor 24. As an example, the first measuring instrument 50 may be a three-phase wattmeter based on a two-wattmeter method, or may be another form of power sensor for measuring the power consumption of the compressor motor 24. The first measuring instrument 50 may be connected to the controller 120 for communication via a wire or wireless method. The compressor power signal E1 indicating the power consumption of the compressor motor 24 measured by the first measuring instrument 50 may be input from the first measuring instrument 50 to the controller 120.

[0037] In addition, the controller 120 may also obtain the power consumption of the compressor motor 24 by other known methods, and in this case, the ultra-low temperature refrigerator 10 does not need to have the first measuring instrument 50. For example, the compressor inverter 25 may be configured to detect the power consumption of the compressor motor 24 based on the current and voltage supplied to the compressor motor 24, and the controller 120 may obtain the power consumption of the compressor motor 24 from the compressor inverter 25. Alternatively, the controller 120 may also obtain a signal indicating the magnitude of the current and voltage supplied to the compressor motor 24 from the compressor inverter 25, thereby obtaining the power consumption of the compressor motor 24.

[0038] As is known, the compressor 12 may have various other components not shown. For example, an oil separator, an adsorber, etc. may be provided on the working gas flow path on the discharge side. A storage tank and other components may be provided on the working gas flow path on the suction side. In addition, the compressor 12 may be provided with an oil circulation system for cooling the compressor body 22 with oil or a cooling system for cooling the oil with cooling water.

[0039] The expander 14 includes a refrigerator cylinder 16 and a displacer assembly 18. The refrigerator cylinder 16 guides the linear reciprocating motion of the displacer assembly 18 and forms expansion chambers 32 and 34 of the working gas between the refrigerator cylinder 16 and the displacer assembly 18. In addition, the expander 14 includes a pressure switching valve 40 that determines the start timing of supplying the working gas to the expansion chamber and the start timing of exhausting the working gas from the expansion chamber.

[0040] In this specification, in order to explain the positional relationship between the components of the cryogenic refrigerator 10, for convenience, the side close to the upper dead point of the axial reciprocating movement of the displacer is marked as "up", and the side close to the lower dead point is marked as "down". The upper dead point is the position of the displacer when the volume of the expansion space becomes the largest, and the lower dead point is the position of the displacer when the volume of the expansion space becomes the smallest. When the cryogenic refrigerator 10 is running, a temperature gradient is generated in which the temperature decreases from the upper axial direction to the lower axial direction, so the upper side can also be called the high temperature side, and the lower side can be called the low temperature side.

[0041] The refrigerator cylinder 16 has a first cylinder 16a and a second cylinder 16b. As an example, the first cylinder 16a and the second cylinder 16b are cylindrical components, and the diameter of the second cylinder 16b is smaller than the diameter of the first cylinder 16a. The first cylinder 16a and the second cylinder 16b are coaxially arranged, and the lower end of the first cylinder 16a is rigidly connected to the upper end of the second cylinder 16b.

[0042] The displacer assembly 18 includes a first displacer 18a and a second displacer 18b connected to each other, and they move integrally. As an example, the first displacer 18a and the second displacer 18b are cylindrical components, and the diameter of the second displacer 18b is smaller than the diameter of the first displacer 18a. The first displacer 18a and the second displacer 18b are coaxially arranged.

[0043] The first displacer 18a is accommodated in the first cylinder 16a, and the second displacer 18b is accommodated in the second cylinder 16b. The first displacer 18a is reciprocable in the axial direction along the first cylinder 16a, and the second displacer 18b is reciprocable in the axial direction along the second cylinder 16b.

[0044] like Figure 3 As shown, the first displacer 18a accommodates the first cold storage device 26. The first cold storage device 26 is formed by filling a metal wire mesh such as copper or other appropriate first cold storage material into the cylindrical main body of the first displacer 18a. The upper cover and the lower cover of the first displacer 18a can be in the form of parts different from the main body of the first displacer 18a, and the upper cover and the lower cover of the first displacer 18a can be fixed to the main body by appropriate methods such as fastening and welding, thereby, the first cold storage material is accommodated in the first displacer 18a.

[0045] Similarly, the second displacer 18b accommodates the second regenerator 28. The second regenerator 28 is formed by filling a non-magnetic regenerator material such as bismuth, HoCu, etc. into a cylindrical main body of the second displacer 18b. 2 The second cold storage material may be formed of a magnetic cold storage material such as a magnetic cold storage material or other appropriate second cold storage material. The second cold storage material may be formed into a granular shape. The upper cover and the lower cover of the second displacer 18b may be in the form of components different from the main body of the second displacer 18b, and the upper cover and the lower cover of the second displacer 18b may be fixed to the main body by appropriate methods such as fastening and welding, thereby the second cold storage material is accommodated in the second displacer 18b.

[0046] The displacer assembly 18 forms a room temperature chamber 30, a first expansion chamber 32, and a second expansion chamber 34 inside the refrigerator cylinder 16. In order to perform heat exchange with a desired object or medium to be cooled by the ultra-low temperature refrigerator 10, the expander 14 has a first cooling stage 33 and a second cooling stage 35. The room temperature chamber 30 is formed between the upper cover portion of the first displacer 18a and the upper portion of the first cylinder 16a. The first expansion chamber 32 is formed between the lower cover portion of the first displacer 18a and the first cooling stage 33. The second expansion chamber 34 is formed between the lower cover portion of the second displacer 18b and the second cooling stage 35. The first cooling stage 33 is fastened to the lower portion of the first cylinder 16a in a manner surrounding the first expansion chamber 32, and the second cooling stage 35 is fastened to the lower portion of the second cylinder 16b in a manner surrounding the second expansion chamber 34. The first cooling stage 33 and the second cooling stage 35 are formed of, for example, pure copper (for example, oxygen-free copper, tough pitch copper, etc.) or other high thermal conductivity metals.

[0047] The first regenerator 26 is communicated with the room temperature chamber 30 through a working gas flow path 36a formed in the upper cover portion of the first displacer 18a, and is communicated with the first expansion chamber 32 through a working gas flow path 36b formed in the lower cover portion of the first displacer 18a. The second regenerator 28 is communicated with the first regenerator 26 through a working gas flow path 36c formed from the lower cover portion of the first displacer 18a to the upper cover portion of the second displacer 18b. Furthermore, the second regenerator 28 is communicated with the second expansion chamber 34 through a working gas flow path 36d formed in the lower cover portion of the second displacer 18b.

[0048] In order to guide the working gas flow between the first expansion chamber 32, the second expansion chamber 34 and the room temperature chamber 30 to the first cold storage device 26 and the second cold storage device 28 instead of the gap between the refrigerator cylinder 16 and the displacer assembly 18, a first seal 38a and a second seal 38b may be provided. The first seal 38a may be installed on the upper cover of the first displacer 18a in a manner arranged between the first displacer 18a and the first cylinder 16a. The second seal 38b may be installed on the upper cover of the second displacer 18b in a manner arranged between the second displacer 18b and the second cylinder 16b.

[0049] like Figure 2 As shown, the expander 14 includes a refrigerator housing 20 that accommodates a pressure switching valve 40. The refrigerator housing 20 is combined with the refrigerator cylinder 16 to form an airtight container that accommodates the pressure switching valve 40 and the displacer assembly 18. The refrigerator housing 20 and the refrigerator cylinder 16 are made of metal materials such as stainless steel or other suitable high-strength materials, so as to withstand the pressure difference between the inside and the outside as an airtight container.

[0050] like Figure 3As shown, the pressure switching valve 40 is configured to include a high-pressure valve 40a and a low-pressure valve 40b, thereby generating periodic pressure changes in the refrigerator cylinder 16. The working gas outlet of the compressor 12 is connected to the room temperature chamber 30 via the high-pressure valve 40a, and the working gas intake of the compressor 12 is connected to the room temperature chamber 30 via the low-pressure valve 40b. The high-pressure valve 40a and the low-pressure valve 40b are configured to selectively open and close alternately (that is, during the period when one valve is open, the other valve is in a closed state).

[0051] The pressure switching valve 40 may be in the form of a rotary valve. That is, the pressure switching valve 40 may be configured to alternately open and close the high-pressure valve 40a and the low-pressure valve 40b by rotating and sliding the valve disc relative to the stationary valve body. At this time, the expander motor 42 may be connected to the pressure switching valve 40 to rotate the valve disc of the pressure switching valve 40. For example, the pressure switching valve 40 is configured so that the valve rotation axis and the rotation axis of the expander motor 42 are coaxial.

[0052] Alternatively, the high-pressure valve 40 a and the low-pressure valve 40 b may be valves that can be controlled individually. In this case, the pressure switching valve 40 may not be connected to the expander motor 42 .

[0053] The expander 14 includes an expander motor 42 and a motion conversion mechanism 43. The expander motor 42 is a driving source for driving the expander 14, for example, an electric motor driven by three-phase alternating current. The expander motor 42 is mounted on the refrigerator housing 20. Similar to the pressure switching valve 40, the motion conversion mechanism 43 is also accommodated in the refrigerator housing 20.

[0054] The expander motor 42 is connected to the displacer drive shaft 44 via a motion conversion mechanism 43 such as a scotch yoke mechanism. The motion conversion mechanism 43 converts the rotational motion output by the expander motor 42 into a linear reciprocating motion of the displacer drive shaft 44. The displacer drive shaft 44 extends from the motion conversion mechanism 43 into the room temperature chamber 30 and is fixed to the upper cover of the first displacer 18a. The rotation of the expander motor 42 is converted by the motion conversion mechanism 43 into an axial reciprocating motion of the displacer drive shaft 44, whereby the displacer assembly 18 reciprocates linearly along the axial direction in the refrigerator cylinder 16.

[0055] Furthermore, the ultra-low temperature refrigerator 10 is provided with an expander inverter 45 for controlling the operating frequency (i.e., rotation speed) of the expander motor 42 according to the expander control signal C2 from the controller 120. In this example, the expander inverter 45 is mounted on the compressor 12, but is not limited to this, and can also be mounted on the expander 14. The expander inverter 45 is configured to convert the AC power input from the power supply 46 to the expander inverter 45 into an AC power having a frequency different therefrom, and supply the converted AC power to the expander motor 42. The operating frequency of the expander motor 42 can be controlled by the expander inverter 45 within the range of 30 Hz to 100 Hz or within the range of 40 Hz to 70 Hz.

[0056] In order to measure the power consumption of the expander motor 42, a second measuring instrument 51 may be provided. The second measuring instrument 51 may be provided on the power supply wiring that connects the expander inverter 45 to the expander motor 42. As an example, the second measuring instrument 51 may be, for example, a three-phase wattmeter based on a two-wattmeter method, or may be a power sensor of other forms that measures the power consumption of the expander motor 42. The second measuring instrument 51 may be connected to the controller 120 in a wired or wireless manner for communication. The expander power signal E2 indicating the power consumption of the expander motor 42 measured by the second measuring instrument 51 may be input from the second measuring instrument 51 to the controller 120.

[0057] In addition, the controller 120 may also obtain the power consumption of the expander motor 42 by other known methods, and in this case, the ultra-low temperature refrigerator 10 does not need to have the second measuring instrument 51. For example, the expander inverter 45 may be configured to detect the power consumption of the expander motor 42 based on the current and voltage supplied to the expander motor 42, and the controller 120 may obtain the power consumption of the expander motor 42 from the expander inverter 45. Alternatively, the controller 120 may also obtain a signal indicating the magnitude of the current and voltage supplied to the expander motor 42 from the expander inverter 45, thereby obtaining the power consumption of the expander motor 42.

[0058] In addition, a first temperature sensor 52 for measuring the temperature of the first cooling stage 33 and a second temperature sensor 53 for measuring the temperature of the second cooling stage 35 may be provided. The first temperature sensor 52 may be mounted on the first cooling stage 33. The second temperature sensor 53 may be mounted on the second cooling stage 35. The first temperature sensor 52 and the second temperature sensor 53 may be connected to the controller 120 in a wired or wireless manner for communication. A first-level temperature signal T1 indicating the first cooling temperature measured by the first temperature sensor 52 may be input from the first temperature sensor 52 to the controller 120. A second-level temperature signal T2 indicating the second cooling temperature measured by the second temperature sensor 53 may be input from the second temperature sensor 53 to the controller 120.

[0059] In addition, the cryogenic refrigerator 10 does not necessarily have to include the first temperature sensor 52 and the second temperature sensor 53. Instead of installing the first temperature sensor 52 and the second temperature sensor 53 on the first cooling stage 33 and the second cooling stage 35, the first temperature sensor 52 and the second temperature sensor 53 may be provided on the superconducting magnet device 100. In this case, the first temperature sensor 52 may be installed on the first cooling stage 33 and the second cooling stage 35. Figure 1 The second temperature sensor 53 may be mounted on the radiation shield 106 shown in FIG. 1 and provide the first temperature signal T1 to the controller 120. Figure 1 The superconducting coil 102 is shown, and a level 2 temperature signal T2 is provided to the controller 120.

[0060] In this embodiment, an interface 110 is provided for the user to input settings for controlling the ultra-low temperature refrigerator 10 to the controller 120. As an exemplary structure, the interface 110 can be an operation panel mounted on the compressor 12, which can be installed on the compressor frame 23. The interface 110 is provided with input components such as operation buttons, keyboards, touch screens, etc. for receiving user input. Data representing the settings input by the user is sent from the interface 110 to the controller 120. In addition, the interface 110 may also have notification components such as a display, a warning light, a speaker, etc. for presenting the settings input by the user or other information related to the ultra-low temperature refrigerator 10 to the user.

[0061] As described later, the interface 110 may be configured to accept a user's selection of a plurality of performance parameters of the cryogenic refrigerator 10 and generate an operation mode setting S1 representing the selected plurality of performance parameters.

[0062] The controller 120 is configured to control the cryogenic refrigerator 10. In this embodiment, as described below, the controller 120 may be configured to receive the set operation mode S1 from the interface 110 and control a plurality of operation parameters of the cryogenic refrigerator 10 that affect the selected plurality of performance parameters.

[0063] The internal structure of the controller 120 can be realized by components or circuits headed by a CPU or memory of a computer in terms of hardware structure, and can be realized by a computer program, etc. in terms of software structure, but is appropriately depicted in the figure as functional blocks realized by their cooperation. Those skilled in the art should understand that these functional blocks can be realized in various forms by a combination of hardware and software.

[0064] For example, the controller 120 can be implemented by a combination of a processor (hardware) such as a CPU (Central Processing Unit) or a microcomputer and a software program executed by the processor (hardware). Such a hardware processor can be composed of a programmable logic device such as an FPGA (Field Programmable Gate Array), or a control circuit such as a programmable logic controller (PLC). The software program can be a computer program for causing the controller 120 to execute control of the ultra-low temperature refrigerator 10.

[0065] In addition, the interface 110 and the controller 120 do not have to be mounted on the compressor 12 as described above, and other configurations may be adopted. For example, the interface 110 and the controller 120 may also be mounted on the expander 14. Alternatively, the interface 110 and the controller 120 may also be configured away from the cryogenic refrigerator 10 and be connected to the cryogenic refrigerator 10 for communication.

[0066] According to the above structure, when the compressor 12 and the expander motor 42 of the ultra-low temperature refrigerator 10 are running, periodic volume changes and pressure changes of the working gas synchronized therewith are generated in the first expansion chamber 32 and the second expansion chamber 34. Typically, in the intake process, by closing the low-pressure valve 40b and opening the high-pressure valve 40a, the high-pressure working gas flows from the compressor 12 through the high-pressure valve 40a into the room temperature chamber 30, and is supplied to the first expansion chamber 32 through the first cold storage device 26, and then supplied to the second expansion chamber 34 through the second cold storage device 28. As a result, the first expansion chamber 32 and the second expansion chamber 34 rise from low pressure to high pressure. At this time, the displacer assembly 18 moves upward from the lower dead center to the upper dead center, and the volume of the first expansion chamber 32 and the second expansion chamber 34 increases. If the high-pressure valve 40a is closed, the intake process ends.

[0067] In the exhaust process, the high-pressure valve 40a is closed and the low-pressure valve 40b is opened, so that the high-pressure first expansion chamber 32 and the second expansion chamber 34 are opened to the low-pressure working gas suction port of the compressor 12, so that the working gas expands in the first expansion chamber 32 and the second expansion chamber 34, and as a result, the low-pressure working gas is discharged from the first expansion chamber 32 and the second expansion chamber 34 to the room temperature chamber 30 through the first regenerator 26 and the second regenerator 28. At this time, the displacer assembly 18 moves downward from the top dead center to the bottom dead center, and the volume of the first expansion chamber 32 and the second expansion chamber 34 decreases. The working gas is recovered from the expander 14 through the low-pressure valve 40b to the compressor 12. If the low-pressure valve 40b is closed, the exhaust process is completed.

[0068] In this way, a refrigeration cycle such as a GM cycle is formed, and the first cooling stage 33 and the second cooling stage 35 are cooled to a desired ultra-low temperature. The first cooling stage 33 can be cooled to a first cooling temperature in the range of about 30K to about 70K, for example. The second cooling stage 35 can be cooled to a second cooling temperature lower than the first cooling temperature (for example, about 1K to about 4K). Therefore, the superconducting coil 102 can be cooled to a critical temperature or less, and the superconducting magnet device 100 can be operated.

[0069] Figure 4 1 is a flowchart showing an example of an operating method of a superconducting device cooling apparatus according to an embodiment of the present invention. The method includes: a step (S10) in which the interface 110 accepts a user's selection of a plurality of performance parameters of a cryogenic refrigerator 10; and a step (S20) in which the controller 120 controls a plurality of operating parameters of the cryogenic refrigerator 10 that affect the selected plurality of performance parameters.

[0070] The interface 110 may be configured to present various performance parameters of the cryogenic refrigerator 10 to the user as candidates for selection. For example, the interface 110 may display these candidate performance parameters on a display. The user may refer to this display and select the performance parameter of interest on the interface 110, thereby being able to input the selection of the performance parameter into the interface 110.

[0071] The multiple performance parameters of the cryogenic refrigerator 10 presented to the user may be at least three parameters representing the performance of the cryogenic refrigerator 10. The at least three parameters may include the first stage temperature of the cryogenic refrigerator 10, the second stage temperature of the cryogenic refrigerator 10, and the power consumption of the cryogenic refrigerator 10. The first stage temperature, the second stage temperature, and the power consumption of the cryogenic refrigerator 10 may affect the operation of the superconducting device cooled by the cryogenic refrigerator 10, and therefore are representative performance parameters of the cryogenic refrigerator 10 that the user is highly concerned about.

[0072] The interface 110 may be configured to accept a selection of at most two performance parameters from the candidate of selectable performance parameters. The selected performance parameters may be one or two performance parameters of the first stage temperature of the cryogenic refrigerator 10, the second stage temperature of the cryogenic refrigerator 10, and the power consumption of the cryogenic refrigerator 10.

[0073] The user's selection of multiple performance parameters of the cryogenic refrigerator 10 may include a priority ranking of the performance parameters. Therefore, the selected multiple performance parameters may include a first performance parameter having a first priority and a second performance parameter having a second priority. The first priority and the second priority are based on the priority ranking performed by the user. The first priority represents a higher priority than the second priority. The controller 120 may be configured to control multiple operating parameters in a manner that improves the first performance parameter in priority to the second performance parameter.

[0074] When a maximum of two performance parameters are selected together with the priority sorting, the interface 110 can generate 9 different operation mode settings S1. That is, when only one performance parameter is selected, the following three modes (operation modes 1 to 3) are used, and when two performance parameters are selected together with the priority sorting, the following modes (operation modes 4 to 9) are used. In addition, below, operation modes 4 to 9 are recorded in order of high priority, that is, the first performance parameter with the first priority and the second performance parameter with the second priority are recorded in sequence from the left.

[0075] Operation mode 1: 2-level temperature

[0076] Operation mode 2: 1st temperature

[0077] Operation Mode 3: Power Consumption

[0078] Operation mode 4: 2nd temperature, 1st temperature

[0079] Operation mode 5: 1st temperature, 2nd temperature

[0080] Operation mode 6: 2 levels of temperature and power consumption

[0081] Operation mode 7: power consumption, 2nd level temperature

[0082] Operation mode 8: Level 1 temperature, power consumption

[0083] Operation mode 9: power consumption, temperature level 1

[0084] The interface 110 may also present all or part of the operation modes 1 to 9 to the user as selection candidates instead of presenting the performance parameters themselves to the user as selection candidates.

[0085] For the convenience of selection, these operation modes may be given names in advance, and the interface 110 may present such operation mode names for selection. For example, the operation modes 3, 7, and 9 that prioritize power consumption may be given operation mode names such as power consumption mode 1, power consumption mode 2, and power consumption mode 3, respectively (or, in the case where the superconducting magnet device 100 is an MRI device, for the user, compared with the daytime, the operation at night may prioritize reducing power consumption, so they may also be named night mode 1, night mode 2, and night mode 3, respectively).

[0086] Operation mode 4 can be named as standard operation mode. Operation mode 1 and operation mode 6 can be named as emergency mode 1 and emergency mode 2, respectively. Operation mode 1 only prioritizes maintaining level 2 temperature, so it can help delay its occurrence as much as possible under conditions where a sudden shutdown (disappearance of superconductivity) is likely to occur. Operation mode 6 gives the highest priority to maintaining level 2 temperature and second priority to power consumption, so it can help make the auxiliary power supply durable under conditions where the superconducting device is operated by an auxiliary power supply as a countermeasure for power outages. Operation mode 5, which prioritizes maintaining level 1 temperature, can be named as a time-dependent aging countermeasure mode. The time-dependent aging of the ultra-low temperature refrigerator 10 often manifests itself as a rise in level 1 temperature, so operation mode 5 can help mitigate the effects of time-dependent aging.

[0087] The interface 110 may be configured to receive a target value of the selected performance parameter from the user. Thus, the user can not only select a performance parameter but also set a target value that the performance parameter should meet. The operation mode setting S1 may include a target value of the performance parameter set by the user.

[0088] like Figure 2 As shown, if the interface 110 accepts the user's selection of multiple performance parameters of the cryogenic refrigerator 10 , an operation mode setting S1 representing the selected multiple performance parameters is generated and output to the controller 120 . The operation mode setting S1 is stored in the controller 120 .

[0089] The controller 120 may include a plurality of control algorithms 122 corresponding to different operation mode settings S1 (for example, the controller 120 may include nine control algorithms 122 corresponding to operation modes 1 to 9, respectively). Each control algorithm 122 may be configured to control a plurality of operation parameters of the cryogenic refrigerator 10 in a manner that improves at least one of the plurality of performance parameters selected in the corresponding operation mode setting S1.

[0090] Therefore, the controller 120 may be configured to receive the operation mode setting S1 from the interface 110 , select a control algorithm 122 corresponding to the operation mode setting S1 from a plurality of control algorithms 122 , and control a plurality of operation parameters of the cryogenic refrigerator 10 according to the selected control algorithm 122 .

[0091] Figure 5 1 is a flowchart showing an example of a control algorithm 122 used in the method for operating the superconducting device cooling apparatus according to the embodiment. The control algorithm 122 includes a step ( Figure 4 S20) is executed. Figure 5As shown, the control algorithm 122 includes: a step (S21) of acquiring the current value of the performance parameter selected in the corresponding operating mode setting S1; a step (S22) of comparing the acquired current value of the performance parameter with the target value; and a step (S23) of controlling the operating parameters of the ultra-low temperature refrigerator 10 according to the comparison result.

[0092] When the selected performance parameter is the first-stage temperature of the cryogenic refrigerator 10, the controller 120 can obtain the current value of the first-stage temperature from the first-stage temperature signal T1 from the first temperature sensor 52. Similarly, when the selected performance parameter is the second-stage temperature of the cryogenic refrigerator 10, the controller 120 can obtain the current value of the second-stage temperature from the second-stage temperature signal T2 from the second temperature sensor 53.

[0093] When the selected performance parameter is the power consumption of the cryogenic refrigerator 10, the controller 120 can obtain the current value of the power consumption of the cryogenic refrigerator 10 from the compressor power signal E1 from the first measuring instrument 50 and the expander power signal E2 from the second measuring instrument 51. The power consumption of the cryogenic refrigerator 10 can be obtained as the sum of the power consumption of the compressor motor 24 and the power consumption of the expander motor 42. In addition, as described above, the controller 120 can also obtain the current and voltage supplied to the compressor motor 24 and the expander motor 42, respectively, and calculate the power consumption of the cryogenic refrigerator 10 based on them.

[0094] As described above, the target value of the performance parameter compared with the current value of the acquired performance parameter may be a value set by the user. Alternatively, if the target value is not set by the user, the controller 120 may use a predetermined target value of each performance parameter or a target value set by the controller 120.

[0095] The controller 120 compares the current value of the acquired performance parameter with the target value and generates a comparison result. According to the magnitude relationship between the current value and the target value, the comparison result can be any one of the following three states: state A to state C.

[0096] State A: The current value is less than (lower than) the target value.

[0097] State B: The current value is equal to the target value.

[0098] State C: The current value is greater than (higher than) the target value.

[0099] In addition, the "current value equals the target value" of state B does not only include the case where the current value is strictly consistent with the target value, but also includes the case where the current value is within the allowable range including the target value. The allowable range may be a range of a specified ratio or a specified amount of the target value (for example, within ±5% of the target value, etc.). State A (or state C) may indicate that the current value exceeds the allowable range (or does not satisfy the allowable range).

[0100] When the selected performance parameter is the first-stage temperature, the second-stage temperature or the power consumption of the ultra-low temperature refrigerator 10, if the comparison result is state A or state B, it can be considered that the performance parameter meets the target value. On the other hand, when the comparison result is state C, it can be considered that the performance parameter does not meet the target value.

[0101] The controller 120 may cause the interface 110 to perform an action based on the comparison result, thereby presenting information indicating that the performance parameter meets the target value to the user, or presenting information indicating that the performance parameter does not meet the target value (i.e., a warning). For example, in order to issue a warning to the user, the controller 120 may light up a warning light provided on the interface 110.

[0102] Together with or in lieu of presenting information to the user, the controller 120 may control the operating parameters of the cryogenic refrigerator 10 in a manner that reduces the deviation between the current value of the acquired performance parameter and the target value. For example, when the current value of the acquired performance parameter does not meet the target value (i.e., when the comparison result is state C), the controller 120 may control the operating parameters of the cryogenic refrigerator 10 in a manner that changes the value of the performance parameter toward the target value (e.g., reduces the value of the performance parameter).

[0103] The controller 120 can select at least one operating parameter from the multiple operating parameters of the ultra-low temperature refrigerator 10 according to the comparison result, and control the selected operating parameter. At this time, the control algorithm 122 can predefine which operating parameter to control according to the comparison result (i.e., respectively for multiple states). Therefore, the controller 120 can select the operating parameter of the control object with reference to the comparison result.

[0104] The controller 120 may be configured to determine a value of an operating parameter of a controlled object. The controller 120 may determine a new value of the operating parameter by adding a certain amount of change to a current value of the operating parameter. The amount of change may be a positive value or a negative value, thereby increasing or decreasing the value of the operating parameter. The amount of change may be a fixed value or a variable value that changes according to conditions.

[0105] The operating parameters of the cryogenic refrigerator 10 are operable parameters that affect the performance parameters of the cryogenic refrigerator 10 , for example, they may be the operating frequency of the compressor motor 24 or the operating frequency of the expander motor 42 .

[0106] Figure 6 (a) shows the relationship between the first-stage temperature and the operating frequency of the expander motor 42 when the operating frequency of the compressor motor 24 is 40 Hz, 50 Hz, 60 Hz, and 70 Hz, respectively. Figure 6 As shown in (a), the first stage temperature of the cryogenic refrigerator 10 has a tendency to decrease monotonically with the increase of the operating frequency of the compressor motor 24. Therefore, by changing (for example, increasing) the operating frequency of the compressor motor 24, the first stage temperature can be adjusted (for example, reduced).

[0107] Likewise, the first stage temperature has a tendency to decrease monotonically with an increase in the operating frequency of the expander motor 42. By changing (eg, increasing) the operating frequency of the expander motor 42, the first stage temperature can be adjusted (eg, reduced).

[0108] Typically, changing the operating frequency of the compressor motor 24 by a certain amount will result in a greater adjustment in the stage 1 temperature than changing the operating frequency of the expander motor 42 by the same amount. Figure 6 As shown in (a), this trend is significant when the operating frequency of the compressor motor 24 is below 60 Hz. Therefore, when the first-stage temperature of the cryogenic refrigerator 10 is selected as the performance parameter in the operation mode setting S1, it may be more effective to select the operating frequency of the compressor motor 24 as the operation parameter.

[0109] Figure 6 (b) shows the relationship between the second-stage temperature and the operating frequency of the expander motor 42 when the operating frequency of the compressor motor 24 is 40 Hz, 50 Hz, 60 Hz, and 70 Hz. Figure 6 As shown in (b), the second stage temperature of the cryogenic refrigerator 10 has a tendency to decrease monotonically with the increase of the operating frequency of the compressor motor 24. Therefore, by changing (for example, increasing) the operating frequency of the compressor motor 24, the second stage temperature can be adjusted (for example, reduced).

[0110] On the other hand, the second stage temperature has a different trend from the first stage temperature with respect to the operating frequency of the expander motor 42. Specifically, if the operating frequency of the compressor motor 24 is set constant and the operating frequency of the expander motor 42 is changed, the second stage temperature becomes the lowest when the operating frequency of the expander motor 42 is a certain value (for example, Figure 6As shown in (b), when the operating frequency of the compressor motor 24 is 50 Hz, the stage 2 temperature becomes the lowest when the operating frequency of the expander motor 42 is 50 Hz). In other words, when the operating frequency of the expander motor 42 is less than this value, the stage 2 temperature decreases as the operating frequency of the expander motor 42 increases. However, when the operating frequency of the expander motor 42 is greater than this value, the stage 2 temperature increases as the operating frequency of the expander motor 42 increases. Therefore, it cannot be said in general that in order to reduce the stage 2 temperature, it is necessary to increase or decrease the operating frequency of the expander motor 42. This operating frequency dependence of the stage 2 temperature is significantly manifested when the stage 2 temperature is below about 4K.

[0111] Therefore, when the second stage temperature of the cryogenic refrigerator 10 is selected as the performance parameter in the operation mode setting S1, in order to make the second stage temperature lower, it is preferable to control both the operating frequencies of the compressor motor 24 and the expander motor 42 as operating parameters.

[0112] The power consumption of the ultra-low temperature refrigerator 10 basically has a trade-off relationship with the cooling temperature. The power consumption has a tendency to increase monotonically with the increase of the operating frequency of the compressor motor 24. Therefore, by changing (for example, reducing) the operating frequency of the compressor motor 24, the power consumption can be adjusted (for example, reduced). In addition, the power consumption increases or decreases according to the change in the operating frequency of the expander motor 42. Therefore, by changing the operating frequency of the expander motor 42, the power consumption can be adjusted. In the case where the power consumption of the ultra-low temperature refrigerator 10 is selected as the performance parameter in the operating mode setting S1, it may be more effective to select the operating frequency of the compressor motor 24 as the operating parameter.

[0113] When the operating frequency of the compressor motor 24 is controlled, the controller 120 generates a compressor control signal C1 indicating the value of the determined operating frequency of the compressor motor 24, and transmits the compressor control signal C1 to the compressor inverter 25. The compressor inverter 25 receives the compressor control signal C1 and drives the compressor motor 24 at the determined operating frequency.

[0114] Similarly, when the operating frequency of the expander motor 42 is controlled, the controller 120 generates an expander control signal C2 indicating the value of the determined operating frequency of the expander motor 42, and sends the expander control signal C2 to the expander inverter 45. The expander inverter 45 receives the expander control signal C2 and drives the expander motor 42 at the determined operating frequency.

[0115] Since it takes a certain amount of time for the effect of the change in the operating parameters to be reflected in the performance parameters, the controller 120 may wait for a predetermined time after changing the operating parameters. The controller 120 may execute the control algorithm 122 again when the waiting time has passed (S21 to S23).

[0116] In the case where two performance parameters are selected in the operation mode setting S1, the controller 120 obtains the current value of the first performance parameter and the current value of the second performance parameter, and compares the current value of the first performance parameter with the first target value, and compares the current value of the second performance parameter with the second target value. The first target value and the second target value are target values ​​of the first performance parameter and the second performance parameter, respectively. In the case where the operation mode setting S1 includes a priority ranking of the performance parameters, as described above, the first performance parameter can be given the first priority and the second performance parameter can be given the second priority. The comparison result can be any of the following nine states from state Aa to state Cc.

[0117] State Aa: The current value of the first performance parameter is smaller than the first target value and the current value of the second performance parameter is smaller than the second target value.

[0118] State Ab: the current value of the first performance parameter is less than the first target value and the current value of the second performance parameter is equal to the second target value.

[0119] State Ac: the current value of the first performance parameter is smaller than the first target value and the current value of the second performance parameter is larger than the second target value.

[0120] State Ba: the current value of the first performance parameter is equal to the first target value and the current value of the second performance parameter is less than the second target value.

[0121] State Bb: The current value of the first performance parameter is equal to the first target value and the current value of the second performance parameter is equal to the second target value.

[0122] State Bc: the current value of the first performance parameter is equal to the first target value and the current value of the second performance parameter is greater than the second target value.

[0123] State Ca: the current value of the first performance parameter is greater than the first target value and the current value of the second performance parameter is less than the second target value.

[0124] State Cb: the current value of the first performance parameter is greater than the first target value and the current value of the second performance parameter is equal to the second target value.

[0125] State Cc: the current value of the first performance parameter is greater than the first target value and the current value of the second performance parameter is greater than the second target value.

[0126] The controller 120 can cause the interface 110 to operate according to the comparison result, thereby presenting information indicating whether the performance parameter meets the target value to the user. For example, when the first performance parameter does not meet the first target value, the controller 120 can issue a first warning (status Ca, Cb, Cc) regardless of whether the second performance parameter meets the second target value. In this way, the user can be reliably notified that the first performance parameter, which has a higher priority than the second performance parameter, does not meet its target value. When the first performance parameter meets the first target value and the second performance parameter does not meet the second target value, the controller 120 can issue a second warning (status Ac, Bc). Furthermore, when the first performance parameter meets the first target value and the second performance parameter also meets the second target value, the controller 120 can issue a normal notification. The first warning, the second warning, and the normal notification can be presented to the user via the interface 110.

[0127] Together with or in lieu of presenting information to the user, the controller 120 may control a plurality of operating parameters of the cryogenic refrigerator 10 in a manner that improves the first performance parameter in priority over the second performance parameter. In this case, when the first performance parameter does not meet the first target value, the controller 120 may control a first operating parameter that affects the first performance parameter among the plurality of operating parameters, regardless of whether the second performance parameter meets the second target value. The first operating parameter may be controlled in a manner that reduces the deviation between the current value of the first performance parameter and the first target value.

[0128] When the first performance parameter satisfies the first target value and the second performance parameter does not satisfy the second target value, the controller 120 may control a second operating parameter that affects the second performance parameter among the plurality of operating parameters. The second operating parameter may be controlled in a manner that reduces the deviation between the current value of the second performance parameter and the second target value. The second operating parameter may be different from the first operating parameter. The first operating parameter may be the operating frequency of the compressor motor 24 (or the operating frequency of the expander motor 42), and the second operating parameter may be the operating frequency of the expander motor 42 (or the operating frequency of the compressor motor 24).

[0129] Several examples of the control algorithm 122 are described. The first example is the above-mentioned operation mode 4 (a case where the first performance parameter is the second-level temperature and the second performance parameter is the first-level temperature). In an example of the control algorithm 122 corresponding to the operation mode 4, the operation parameters are controlled as follows for each of the nine states Aa to Cc.

[0130] State Aa: Maintain operating parameters.

[0131] State Ab: Maintain operating parameters.

[0132] State Ac: The operating frequency of the compressor motor 24 is increased.

[0133] State Ba: Maintain operating parameters.

[0134] State Bb: Maintain operating parameters.

[0135] State Bc: The operating frequency of the compressor motor 24 is increased.

[0136] State Ca: The operating frequency of the expander motor 42 is changed.

[0137] State Cb: The operating frequency of the expander motor 42 is changed.

[0138] State Cc: The operating frequency of the compressor motor 24 is increased.

[0139] In the six states Aa to Bc, the second stage temperature as the first performance parameter satisfies its target value. In the states Aa, Ab, Ba, and Bb, the first stage temperature as the second performance parameter also satisfies its target value, so the operating parameters are maintained without change.

[0140] In states Ac and Bc, the operating parameters are controlled in such a manner that the second-stage temperature, which is the first performance parameter, satisfies the target value while the first-stage temperature, which is the second performance parameter, satisfies the target value. In state Ac, as a result of the increase in the operating frequency of the compressor motor 24, the first-stage temperature (and the second-stage temperature) is expected to drop and transition to state Ab. In a case where the operating frequency of the compressor motor 24 has reached the maximum value of the adjustable range (for example, 70 Hz), the operating frequency of the expander motor 42 may be increased instead of increasing the operating frequency of the compressor motor 24 (at this time, transition to state Ab or state Bb is expected. In the event of transition to state Cb, a warning is issued). Furthermore, in state Bc, as a result of the increase in the operating frequency of the compressor motor 24, the first-stage temperature (and the second-stage temperature) is expected to drop and transition to state Ab or state Ac.

[0141] In states Ca to Cc, the operating parameters are controlled in such a way that the second-stage temperature, which is the first performance parameter, meets the target value. In states Ca and Cb, the operating frequency of the expander motor 42 increases (or decreases), and as a result, it is expected to transition to any state from states Ba to Bc. If state Ca is maintained even when the operating frequency of the expander motor 42 is optimized, the operating frequency of the compressor motor 24 can be increased (at this time, it is expected to transition to any state from states Ba to Bc. If state Ca is still maintained, a warning is issued). In state Cc, as a result of the increase in the operating frequency of the compressor motor 24, a transition to state Bc or Cb is expected. If state Cc is maintained even in this case, the operating frequency of the expander motor 42 can be reduced (at this time, it is expected to transition to state Bc. If state Cc is still maintained, a warning is issued).

[0142] The second example is operation mode 6 (a case where the first performance parameter is the second-level temperature and the second performance parameter is the power consumption). In an example of the control algorithm 122 corresponding to operation mode 6, the operation parameters are controlled as follows for each of the nine states Aa to Cc.

[0143] State Aa: Maintain operating parameters.

[0144] State Ab: Maintain operating parameters.

[0145] State Ac: The operating frequency of the compressor motor 24 is reduced.

[0146] State Ba: Maintain operating parameters.

[0147] State Bb: Maintain operating parameters.

[0148] State Bc: The operating frequency of the expander motor 42 is changed.

[0149] State Ca: The operating frequency of the compressor motor 24 is increased.

[0150] State Cb: The operating frequency of the compressor motor 24 is increased.

[0151] State Cc: The operating frequency of the compressor motor 24 is increased.

[0152] In the six states Aa to Bc, the second-stage temperature as the first performance parameter satisfies its target value. Among them, in states Aa, Ab, Ba, and Bb, the power consumption as the second performance parameter also satisfies the target value, so the operating parameters are maintained without change. In addition, in states Aa and Ab, the operating frequency of the compressor motor 24 can also be reduced to further reduce the power consumption (in this case, the state Ba can be transitioned).

[0153] In states Ac and Bc, the operating parameters are controlled so that the second stage temperature as the first performance parameter satisfies the target value and the power consumption as the second performance parameter satisfies the target value. In state Ac, as a result of the decrease in the operating frequency of the compressor motor 24, it is expected to transition to state Ab or Bb. In state Bc, as a result of the change in the operating frequency of the expander motor 42, it is expected to transition to state Ab or Bb (if state Bc is still maintained, a warning is issued).

[0154] In states Ca to Cc, the operating parameters are controlled in such a way that the second-stage temperature, which is the first performance parameter, meets the target value. In state Ca, as a result of the increase in the operating frequency of the compressor motor 24, a transition to state Ba or Cb can be achieved. In state Cb, as a result of the increase in the operating frequency of the compressor motor 24, a transition to state Bc or Cc can be achieved. In state Cc, as a result of the increase in the operating frequency of the compressor motor 24, a transition to state Bc can be achieved (in the case of no transition, a transition to state Bc can be achieved by changing the operating frequency of the expander motor 42. In the event that state Cc is still maintained, a warning is issued).

[0155] The third example is operation mode 7 (a case where the first performance parameter is power consumption and the second performance parameter is second-level temperature). In an example of the control algorithm 122 corresponding to operation mode 7, the operation parameters are controlled as follows for each of the nine states Aa to Cc.

[0156] State Aa: Maintain operating parameters.

[0157] State Ab: Maintain operating parameters.

[0158] State Ac: The operating frequency of the expander motor 42 is changed.

[0159] State Ba: Maintain operating parameters.

[0160] State Bb: Maintain operating parameters.

[0161] State Bc: The operating frequency of the expander motor 42 is changed.

[0162] State Ca: The operating frequency of the compressor motor 24 is reduced.

[0163] State Cb: The operating frequency of the compressor motor 24 is reduced.

[0164] State Cc: The operating frequency of the compressor motor 24 is reduced.

[0165] In the six states Aa to Bc, the power consumption as the first performance parameter meets its target value. Among them, in states Aa, Ab, Ba, and Bb, the second-stage temperature as the second performance parameter also meets the target value, so the operating parameters are maintained without change. In addition, in state Aa, the operating frequency of the compressor motor 24 can also be reduced to further reduce the power consumption (in this case, it can be transitioned to state Ab).

[0166] In states Ac and Bc, the operating parameters are controlled in such a way that the power consumption as the first performance parameter meets the target value and the second-stage temperature as the second performance parameter meets the target value. In state Ac, the operating frequency of the expander motor 42 increases (or decreases), and as a result, it is expected to transition to state Ab or Bc. If state Ac is maintained even when the operating frequency of the expander motor 42 is optimized, the operating frequency of the compressor motor 24 can be increased, thereby transitioning to state Ab or Bc. In state Bc, the operating frequency of the expander motor 42 increases (or decreases), and as a result, it is expected to transition to state Ab or Bb (if state Bc is still maintained, a warning is issued).

[0167] In the states Ca to Cc, the operating parameters are controlled so that the power consumption as the first performance parameter meets the target value. In the state Ca, as a result of the operating frequency of the compressor motor 24 decreasing, the state can be transitioned to the state Ba or Cb. In the state Cb, as a result of the operating frequency of the compressor motor 24 decreasing, the state can be transitioned to the state Bb or Bc. In the state Cc, as a result of the operating frequency of the compressor motor 24 decreasing, the state can be transitioned to the state Bc.

[0168] As described at the beginning of this specification, conventional superconducting device cooling devices are usually operated under predetermined operating conditions set by their manufacturers. For example, the cooling device can be operated after sufficient refrigeration capacity is left. In this case, even if various emergency situations or other unexpected situations occur, the superconducting device can be operated stably, which is advantageous. On the other hand, for the user of the superconducting device, for example, from the perspective of energy saving, there is actually not much room for adjusting the operating conditions of the cooling device by his own judgment.

[0169] In contrast, according to the superconducting device cooling device involved in the embodiment, the user can select the performance parameters of the ultra-low temperature refrigerator 10 by himself, so as to achieve the operation state that the user considers ideal. The ultra-low temperature refrigerator 10 controls the operation parameters in a manner so that the selected performance parameters meet the target values, thereby achieving the operation state expected by the user. Moreover, in the case where such an expected operation state is not achieved, the user can be notified of this situation through a warning. Therefore, the usability of the superconducting device cooling device can be improved.

[0170] The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that the present invention is not limited to the above-mentioned embodiments, and various design changes and variations may exist, and such variations are also within the scope of the present invention. Various features described in one embodiment may also be applied to other embodiments. A new embodiment generated by combination has the effects of the combined embodiments.

[0171] In the above embodiment, the first stage temperature, the second stage temperature, and the power consumption are exemplified as the performance parameters of the cryogenic refrigerator 10, but other performance parameters may be used. For example, in the case where the superconducting magnet device 100 is an immersion cooling type, the pressure of the liquid refrigerant tank (for example, a liquid helium tank) in the vacuum container 104 may be used as a performance parameter. Since the liquid refrigerant in the liquid refrigerant tank is cooled by the second cooling stage 35, the pressure of the liquid refrigerant tank is related to the second stage temperature. Therefore, the pressure of the liquid refrigerant tank may be used as a performance parameter instead of the second stage temperature.

[0172] In the above embodiment, the operating frequencies of the compressor motor 24 and the expander motor 42 are exemplified as the operating parameters of the cryogenic refrigerator 10, but other operating parameters may also be used. For example, when a first heater for heating the first cooling stage 33 and / or a second heater for heating the second cooling stage 35 are provided, the output of the heater may also be used as an operating parameter.

[0173] In the above embodiment, a two-stage GM refrigerator is used as an example for description, but the present invention is not limited thereto. In one embodiment, the ultra-low temperature refrigerator 10 may also be a single-stage GM refrigerator. In one embodiment, the ultra-low temperature refrigerator 10 may also be other types of ultra-low temperature refrigerators such as a Solvay refrigerator, a Stirling refrigerator, and a pulse tube refrigerator.

[0174] In the above embodiment, the superconducting magnet device 100 is cooled by the cryogenic refrigerator 10 as an example, but the present invention is not limited thereto. In one embodiment, the cryogenic refrigerator 10 can also provide cryogenic cooling for other superconducting devices such as a device for power transmission using superconductivity, a sensor device using superconductivity, etc.

[0175] The present invention has been described above based on the implementation mode and using specific terms, but the implementation mode only illustrates one aspect of the principle and application of the present invention. Without departing from the scope of the idea of ​​the present invention specified in the technical solution, the implementation mode may have various modifications and configuration changes.

[0176] Industrial Applicability

[0177] The present invention can be used in the field of a superconducting device cooling device and an operating method of a superconducting device cooling device.

[0178] Explanation of symbols

[0179] 10-ultra-low temperature refrigerator, 12-compressor, 14-expander, 24-compressor motor, 25-compressor inverter, 42-expander motor, 45-expander inverter, 110-interface, 120-controller, 122-control algorithm.

Claims

1. A superconducting device cooling device, characterized in that: have: Ultra-low temperature refrigerators, which cool superconducting devices; an interface configured to accept a user's selection of a plurality of performance parameters of the cryogenic refrigerator and generate an operating mode setting representing the selected plurality of performance parameters; and A controller is configured to receive the operating mode setting from the interface and control a plurality of operating parameters of the cryogenic refrigerator that affect the selected plurality of performance parameters.

2. The superconducting device cooling device according to claim 1, characterized in that: The operation mode setting includes a priority ranking of a plurality of performance parameters of the ultra-low temperature refrigerator set by a user, The selected plurality of performance parameters include a first performance parameter having a first priority based on the priority sorting and a second performance parameter having a second priority, wherein the first priority indicates a priority higher than the second priority, The controller is configured to control the plurality of operating parameters so as to improve the first performance parameter with priority over the second performance parameter.

3. The superconducting device cooling device according to claim 2, characterized in that: The controller is configured as follows: comparing the current value of the first performance parameter with the first target value, When the first performance parameter does not satisfy the first target value, a first operating parameter affecting the first performance parameter among the plurality of operating parameters is controlled regardless of whether the second performance parameter satisfies the second target value.

4. The superconducting device cooling device according to claim 3, characterized in that: The controller is configured as follows: comparing the current value of the second performance parameter with the second target value, When the first performance parameter satisfies the first target value and the second performance parameter does not satisfy the second target value, a second operating parameter that affects the second performance parameter among the plurality of operating parameters is controlled.

5. The superconducting device cooling device according to claim 4, characterized in that: The controller is configured as follows: When the first performance parameter does not satisfy the first target value, a first warning is issued regardless of whether the second performance parameter satisfies the second target value. When the first performance parameter satisfies the first target value and the second performance parameter does not satisfy the second target value, a second warning is issued.

6. The superconducting device cooling device according to claim 1, characterized in that: The controller has a plurality of control algorithms corresponding to different operation mode settings, Each control algorithm is configured to control the plurality of operating parameters in a manner to improve at least one performance parameter of the plurality of performance parameters selected in a corresponding operating mode setting.

7. The superconducting device cooling device according to claim 1, characterized in that: The selected multiple performance parameters are two performance parameters of the first stage temperature of the ultra-low temperature refrigerator, the second stage temperature of the ultra-low temperature refrigerator, and the power consumption of the ultra-low temperature refrigerator.

8. The superconducting device cooling device according to claim 1, characterized in that: The cryogenic refrigerator includes an expander and a compressor for supplying refrigerant gas to the expander. The expander includes an expander motor for driving the expander and an expander inverter for controlling an operating frequency of the expander motor. The compressor includes a compressor motor for driving the compressor and a compressor inverter for controlling an operating frequency of the compressor motor. The plurality of operating parameters include an operating frequency of the compressor motor and an operating frequency of the expander motor.

9. A method for operating a superconducting device cooling device, characterized in that: The superconducting device cooling device is provided with an ultra-low temperature refrigerator for cooling the superconducting device, and the method comprises the following steps: Accepting a user's selection of a plurality of performance parameters of the ultra-low temperature refrigerator; and A plurality of operating parameters of the cryogenic refrigerator that affect the selected plurality of performance parameters are controlled.

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