Control systems and related technologies for charging uninsulated / partially insulated superconducting magnets

Abstract

The system includes a superconducting magnet including a coil of superconducting material. The coil includes electrical terminals. The turns of the coil are separated by metallic conductors. A control circuit is coupled to the terminals to drive a current through the coil for charging the superconducting magnet, and is configured to provide a current through the coil that is small enough to avoid quenching effects of the superconducting magnet and large enough to charge the magnet within a predetermined period of time. A cooling structure is thermally coupled to the coil to remove heat generated by charging the superconducting magnet with the current, allowing the current to be large enough to charge the magnet within a predetermined period of time without causing quenching effects.

Description

[Technical Field]

[0001]

[0001] This disclosure relates to superconducting magnets, and more specifically to superconducting magnets using partial insulation and no insulation, and to control systems, apparatus and methods for controlling superconducting magnets. [Background technology]

[0002]

[0002] Superconducting magnets with partial- and / or no-insulation (PI / NI) between superconducting turns may be used because they can be designed to be passively safe during quenching. Quenching is the transition from a superconductor to a normal (i.e., non-superconducting) conductor caused by a superconductor current exceeding thresholds of operating magnetic field, temperature, and / or current density. Quenching can cause a large amount of energy stored in the magnetic field to accumulate as thermal energy in a small volume of magnet, which can damage some or all of the superconducting magnet. This can be avoided by PI / NI magnets by allowing current to flow from around the quench zone to adjacent superconducting turns and / or by electrically coupling the quench to adjacent turns. [Overview of the project]

[0003]

[0003] In the embodiment, the system includes a superconducting magnet, the superconducting magnet itself includes a coil of superconducting material. The coil includes two electrical terminals. The windings of the coil are separated by a metal conductor. A control circuit is coupled to the two terminals to send or drive an electric current through the coil for charging the superconducting magnet. Furthermore, the control circuit is configured to provide through the coil a current that is small enough to avoid the quench effect of the superconducting magnet and large enough to charge the magnet within a predetermined period of time. A cooling structure is thermally coupled to the coil to remove the heat generated by the electric charge of the superconducting magnet, and the current is large enough to charge the magnet within a predetermined period of time without causing a quench effect.

[0004]

[0004] One or more of the following features may be included individually or in combination.

[0005]

[0005] The cooling structure can be configured to maintain the coil temperature at 4K or higher.

[0006]

[0006] The control circuit may include one or more feedback loops.

[0007]

[0007] One or more feedback loops can provide feedback on the coil temperature.

[0008]

[0008] One or more feedback loops can feed back the current passing through the coil.

[0009]

[0009] One or more feedback loops can provide feedback on the magnetic field of the coil.

[0010]

[0010] The control circuit may include a model of a coil.

[0011]

[0011] The model may include a temperature limit for the coil, a current limit for the coil, and a magnetic field limit for the coil.

[0012]

[0012] Temperature limit, current limit, and magnetic field limit can define the range in which the coil functions as a superconductor.

[0013]

[0013] In another embodiment, a method for controlling a superconducting magnetic coil includes driving a current through the superconducting magnetic coil by a variable current source, monitoring the current through the superconducting magnetic coil, the temperature of the superconducting magnetic coil, and the magnetic field about the superconducting magnetic coil by a control circuit, determining a current operating point of the superconducting magnetic coil by comparing the temperature, current, and magnetic field by the control circuit with a model of the superconducting magnetic coil stored in the control circuit, determining a maximum current available for charging the coil based on the operating point and operating range of the superconducting magnetic coil, and adjusting the current to match the maximum current for supplying energy to the superconducting magnetic coil. The model defines an operating range in which the coil functions as a superconductor with respect to the superconducting magnetic coil.

[0014]

[0014] One or more of the following features may be included.

[0015]

[0015] The control circuit can control a cooling system to cool the superconducting magnetic coil when applying the maximum current so that the superconducting magnetic coil remains within the operating range.

[0016]

[0016] The cooling structure can be configured to maintain the temperature of the coil at 4K or higher.

[0017]

[0017] The control circuit can include one or more feedback loops.

[0018]

[0018] One or more feedback loops can feedback the coil temperature.

[0019]

[0019] One or more feedback loops can feedback the current through the coil.

[0020]

[0020] One or more feedback loops can feed back the magnetic field of the coil.

[0021]

[0021] The model may include a temperature limit for the coil, a current limit for the coil, and a magnetic field limit for the coil.

[0022]

[0022] Temperature limits, current limits, and magnetic field limits can define the range in which the coil acts as a superconductor.

[0023]

[0023] The windings of the superconducting magnetic coil can be separated by a metal conductor.

[0024]

[0024] Some embodiments relate to a method for controlling a superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, the method comprising sensing the physical characteristics of the superconducting magnet using a sensor, determining electrical parameters for supplying to the superconducting magnet based on the sensed physical characteristics and a model of the superconducting magnet stored in a computer-readable storage medium using a control circuit, and supplying the determined electrical parameters to the superconducting magnet.

[0025]

[0025] Physical characteristics may include temperature, voltage, current, magnetic field, and / or magnetic flux density.

[0026]

[0026] Electrical parameters may include current and / or voltage.

[0027]

[0027] The model can represent the critical current of the superconductor of a superconducting magnet based on temperature, magnetic field, and / or magnetic flux density.

[0028]

[0028] The method may further include resensing the physical features after a time interval has elapsed since the sensing of the physical features, using a control circuit to redetermine the electrical parameters for supplying the superconducting magnet based on the resensed physical features and model, and providing the redetermined electrical parameters to the superconducting magnet.

[0029]

[0029] Decisions can be made using feedback.

[0030]

[0030] The determination may include calculating the critical current of the superconductor of the superconducting magnet, calculating the error of the critical current with respect to the set value, and setting the electrical parameters based on the error.

[0031]

[0031] Calculating the error may involve dividing the calculated current flowing through the superconductor by the critical current to create a ratio, and then comparing that ratio with a set value.

[0032]

[0032] The determination may include calculating future parameters of the superconducting magnet based on the perceived physical characteristics and model, and setting electrical parameters based on the calculated future parameters.

[0033]

[0033] The model may include a thermal model of the superconducting magnet.

[0034]

[0034] The method may further include determining the degree of cooling based on the model and the perceived physical characteristics, and controlling the cooling system for the superconducting magnet based on the determined degree of cooling.

[0035]

[0035] Some embodiments involve a computer-readable storage medium that stores instructions that cause a method to be performed when executed by a processor.

[0036]

[0036] Some embodiments relate to a device for controlling a superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, the device including a control circuit configured to receive sensed physical characteristics of the superconducting magnet from a sensor, determine electrical parameters for supplying to the superconducting magnet based on the sensed physical characteristics and a model of the superconducting magnet stored in a computer-readable storage medium, and provide the determined electrical parameters to the superconducting magnet.

[0037]

[0037] Physical characteristics may include temperature, voltage, current, magnetic field, and / or magnetic flux density.

[0038]

[0038] Electrical parameters may include current and / or voltage.

[0039]

[0039] The model can represent the critical current of the superconductor of a superconducting magnet based on temperature, magnetic field, and / or magnetic flux density.

[0040]

[0040] The control circuit can be configured to re-sens the physical characteristics after a time interval has elapsed since the sensing of the physical characteristics, to use the control circuit to re-determine the electrical parameters for supplying to the superconducting magnet based on the re-sensed physical characteristics and model, and to provide the re-determined electrical parameters to the superconducting magnet.

[0041]

[0041] Decisions can be made using feedback.

[0042]

[0042] The determination may include calculating the critical current of the superconductor of the superconducting magnet, calculating the error of the critical current with respect to the set value, and setting the electrical parameters based on the error.

[0043]

[0043] Calculating the error may involve dividing the calculated current flowing through the superconductor by the critical current to create a ratio, and then comparing that ratio with a set value.

[0044]

[0044] The determination may include calculating future parameters of the superconducting magnet based on the perceived physical characteristics and setting electrical parameters based on the calculated future parameters.

[0045]

[0045] The model may include a thermal model of the superconducting magnet.

[0046]

[0046] The control circuit can be configured to determine the degree of cooling based on the model and the sensed physical characteristics, and to control the cooling system for the superconducting magnet based on the determined degree of cooling.

[0047]

[0047] Some embodiments relate to a system comprising a superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, and a control circuit, the control circuit being configured to receive sensed physical characteristics of the superconducting magnet from a sensor, determine electrical parameters for supplying power to the superconducting magnet based on the sensed physical characteristics and a model of the superconducting magnet stored in a computer-readable storage medium, and provide the determined electrical parameters to the superconducting magnet.

[0048]

[0048] The above summary is provided as an example and is not intended to limit the scope.

[0049]

[0049] The above features will be understood more fully from the description of the drawings below. The drawings are to help describe and understand the disclosed technology. Since it is often impractical or impossible to illustrate and describe all possible embodiments, the drawings provided show one or more exemplary embodiments. Accordingly, the drawings are not intended to limit the scope of the invention. The same number in the drawings indicates the same element. [Brief explanation of the drawing]

[0050] [Figure 1]

[0050] This is a block diagram of the magnetic coil and control circuit. [Figure 2]

[0051] This is a three-dimensional graph of the operational model of a superconducting magnet. [Figure 3]

[0052] This is a block diagram of an embodiment of a control circuit for a superconducting magnet. [Figure 4]

[0053] This is a simplified perspective view of a tokamak-type nuclear fusion power system. [Figure 4A]

[0054] This is a block diagram of a portion of the magnetic coils in a nuclear fusion power system. [Figure 5]

[0055] This is a perspective view of spiral plates and superconducting tapes used in superconducting magnets. [Figure 6]

[0056] This is a block diagram of a computing device. [Figure 7]

[0057] This is an equiaxial partial cross-sectional view of an MRI system including a control circuit that may be the same as or similar to the control circuits shown in Figures 1 and 3. [Modes for carrying out the invention]

[0051]

[0058] According to one characteristic of the concept described here, it is recognized that reducing and / or completely eliminating insulation in a superconducting magnet means that the voltage generated between the PI / NI superconducting layers (e.g., the induced voltage generated during charging and discharging) can cause current to flow through either conductive layer. This typically involves actually placing a resistor (R) in parallel with the inductance (L) of the superconducting magnet, thereby effectively forming a parallel LR circuit.

[0052]

[0059] Such a situation can be problematic for at least two reasons. Firstly, superconducting magnets are often charged by a current-controlled power source. In PI / NI magnets, the charging or discharging time can be on the order of L / R timescale, which can be quite long for PI / NI magnets with a large L and a small R. For this reason, PI / NI superconducting magnets are typically used only in DC magnets (e.g., those that have a substantially constant current when charged), but the techniques and apparatus described here are not limited in this respect. Secondly, the current flowing through the resistive part of the magnet generates heat. This heat generation is contrary to the need to keep the superconductor at a sufficiently low temperature to maintain its superconducting properties. To keep the superconductor at a sufficiently low temperature, the heat generated in the resistive part of the magnet must be sufficiently removed (e.g., by using a cooling system).

[0053]

[0060] To overcome the limitation of slow charging time, the coil terminals can be effectively overdriven to provide a larger voltage to the inductor and increase the current gradient of the superconductor. However, this also increases the current flowing through the resistive portion of the magnet. A control system is described here, which can control the current and / or voltage supplied to the superconducting magnet in order to reduce or minimize the charging time, and at the same time, to avoid overheating the magnet to a temperature above the temperature at which the superconductor loses its superconducting properties.

[0054]

[0061] This disclosure relates to a control system for superconducting magnets for use in various applications. As described below, a superconducting magnet may include a coil of superconducting material through which an electric current flows and generates a magnetic field.

[0055]

[0062] Before proceeding with the description of the example control circuit used with superconducting magnets, we will explain some introductory concepts. While specific applications may be referenced here, it should be understood that such applications are provided solely to enhance clarity in explaining the broader concepts described here. It should be understood that the concepts, systems, circuits, and techniques described here have applications in a wide variety of fields.

[0056]

[0063] For example, after reading the description provided herein, a person of ordinary skill will readily understand that the concepts, systems, circuits, and techniques described herein are generally applicable to a wide range of applications where high-field magnets may be used (e.g., a wide range of industrial applications), and that the control concepts, control systems, control circuits, and control techniques described herein will facilitate the commercialization of high-field magnets for use in a variety of different applications. Such applications are not limited to, but include, applications in the fields of medicine and life sciences (e.g., magnetic resonance imaging (MRI) and spectroscopy), applications in the fields of chemistry, biochemistry, and biology (e.g., nuclear magnetic resonance (NMR), NMR spectroscopy, electron paramagnetic resonance (EPR), and Fourier transform ion cyclotron resonance (FT-ICR)), applications in particle accelerators and detectors (e.g., use in healthcare applications such as equipment for radiotherapy), applications in equipment for generating and controlling hot hydrogen plasma, applications in the field of transportation, applications in the field of power generation and conversion, applications in heavy industry, applications in weapons and defense, applications in the field of high-energy particle physics, and applications in the field of nuclear fusion power plants (e.g., compact nuclear fusion power plants).

[0057]

[0064] In other words, while this text occasionally refers to the use of high-field magnet assemblies, including the control circuits of the subject matter, in relation to specific applications (e.g., nuclear fusion or MRI), such references are not intended to be limiting and should not be interpreted as limiting. Rather, it should be understood that the control circuits and systems for high-field magnet assemblies provided according to the concepts described herein will find use in a wide variety of applications.

[0058]

[0065] Referring here to Figure 1, the system 100 for controlling the magnetic coil 102 may include a control circuit 101 for monitoring the magnetic coil 102, controlling (and ideally optimizing) current ramping and cooling, and avoiding or at least reducing quench occurrence. The control circuit 101 may be coupled to a variable current or voltage source 104 that drives the current through the magnetic coil 102. The control circuit 101 can change the current through the magnetic coil 102 by controlling the variable current or voltage source 104.

[0059]

[0066] A cooling system can be coupled to the magnetic coil 102 to control its temperature. In some embodiments, the temperature setpoint of the cooling system can be variable and can be set by a control circuit 101 based on a model of the magnetic coil 102 described later. However, in some embodiments, the cooling system can have a constant temperature setpoint. The cooling system may include a cooling channel 106 that is thermally coupled to the magnetic coil 102. For example, the cooling channel 106 may be configured to allow a low-temperature fluid (e.g., liquid helium or liquid nitrogen) or another cooling fluid to flow through it to remove heat from the magnetic coil 102. Alternatively or additionally, a conduction cooling system can be used that conducts heat far away through a heat conductor without flowing a low-temperature fluid through the cooling channel 106. In some embodiments, the cooling channel 106 can be thermally coupled to the magnetic coil 102 in close proximity to maximize the cooling that the fluid cooling channel 106 can provide to the coil. For example, the cooling channel 106 can be physically coupled to a heat conductor (e.g., a copper strip or plate not shown) which is directly physically coupled to the magnetic coil 102.

[0060]

[0067] In the embodiment, the cooling channel 106 may include a pipe or tube through which a cooling fluid flows. A pump 108 may inject the cooling fluid through the cooling channel 106 and circulate it through the magnetic coil 102 to remove heat. Although not shown, the cooling system may also include a condenser, compressor, cooling vat, cooling tower, etc.

[0061]

[0068] In this embodiment, the magnetic coil 102 may include a so-called high-temperature superconductor. In this case, the cooling system may be configured to maintain the temperature of the magnetic coil 102 at 4 Kelvin, 10 Kelvin, or higher, but low enough to allow the magnet to maintain the superconducting properties of the high-temperature superconductor while it is operating.

[0062]

[0069] The control circuit 101 can also be coupled to control the cooling system. For example, the control circuit 101 can control a pump 108, a condenser (not shown), a compressor (not shown), or other elements of the cooling system to cool the magnetic coil 102. In some embodiments, the control circuit 101 can control the amount of cooling that the cooling system provides to the magnetic coil 102 by operating the pump 108 at various speeds, adjusting valves, or switching the compressor and condenser on and off. In other embodiments, the cooling system can cool the magnetic coil at a constant rate.

[0063]

[0070] The control circuit 101 can monitor the state of the magnetic coil 102. For example, the control circuit 101 can be coupled to a magnetic field sensor 1110 to monitor the strength of the magnetic field generated by the magnetic coil 102. Although shown as a loop sensor, the magnetic field sensor 1110 can be a Hall effect sensor, a magnetoresistive element, or any type of magnetic field detection device.

[0064]

[0071] The control circuit 101 can be coupled to a temperature sensor 112, which can be thermally coupled to a magnetic coil 102, allowing the control circuit 101 to monitor the temperature of the magnetic coil 102. In some embodiments, one temperature sensor 112 may be included. In other embodiments, multiple temperature sensors can be used to sense the temperature at various locations on the magnetic coil 102.

[0065]

[0072] Furthermore, since the control circuit 101 controls the current or voltage source 104, the control circuit 101 can monitor the amount of current flowing through the magnetic coil 102 or the voltage across the magnetic coil 102. In embodiments, the system 100 may include a current or voltage sensor (for example, coupled to the magnetic coil 102 and / or the current source 104) that can sense the amount of current flowing through the magnetic coil 102 and / or the voltage across the magnetic coil 102. In this case, the control circuit 101 can be coupled to the current or voltage sensor, and this current or voltage sensor can be used to monitor the current flowing through the magnetic coil 102 or the voltage across the magnetic coil 102. In embodiments, such measurements can be performed at the terminals of the magnetic coil connected to the current or voltage sensor 104.

[0066]

[0073] The control circuit 101 can be implemented as a custom logic circuit, a programmed FPGA, a software-programmed general-purpose computer, a software-programmed application-specific computer, or any type of circuit, system, or computing device that can act as a control system for cooling and controlling the current flowing through the magnetic coil 102. In embodiments, the control circuit 101 may include a memory 114 that can store data used by the control circuit 101. The memory 114 may be a non-volatile memory such as an EPROM, a volatile memory on which data used by the control circuit 101 is loaded, or a hard-programmed memory such as a logic circuit acting as memory. In embodiments, the memory 114 may store data representing the operating model of the magnetic coil 102.

[0067]

[0074] Referring now to Figure 2, the three-dimensional graph represents an operating model 200 of the magnetic coil 102 (and / or superconducting tape) according to several embodiments. The J-axis represents the current density flowing through the superconductor, the B-axis represents the magnetic field or magnetic flux density to which the magnetic coil or superconducting tape is exposed (generated by the current flowing through the magnetic coil 102 and some magnetic field source outside the magnetic coil 102), and the T-axis represents the temperature of the magnetic coil (e.g., coil 102) and / or superconducting tape.

[0068]

[0075] Curve 202 represents the superconductivity boundary of a magnetic coil (e.g., coil 102) and / or superconducting tape. The magnetic coil (or tape) can act as a superconductor when operating below curve 202. However, if the current density J, magnetic field or magnetic flux density B, and / or temperature T become too high and the operating point shifts above curve 202, the magnetic coil (or tape) loses all or part of its superconducting properties and begins to quench.

[0069]

[0076] Using Model 200, the control circuit 101 can provide the maximum rate change of current to the magnetic coil 102 in order to supply energy to the magnetic coil 102 without allowing quenching to occur in the magnetic coil 102. For example, point 204 represents the initial state of the magnetic coil 102 before any current flows through it (i.e., point 204 is when the temperature (T) is finite, the current density (J) is zero, and the magnetic field or magnetic flux density (B) is zero). To supply energy to the magnetic coil 102, the control circuit 101 can provide terminal currents and / or voltages such that the current density J of the superconductor is less than or equal to point 206, so as not to cause quenching in the magnetic coil 102. In general, as the current density J increases, the magnetic field B increases proportionally. As the magnetic field B and temperature T change, the control circuit 101 can change the amount of current flowing through the magnetic coil 102 and / or the amount of cooling provided to the magnetic coil 102 so that the magnetic coil 102 remains in a superconducting state. The control circuit 101 can reduce (and ideally minimize) the time required to supply energy to the magnetic coil 102 by providing an increased current (and ideally the maximum or near-maximum current) to the magnetic coil 102 while maintaining the operating point of the magnetic coil 102 below the plane 202. In some embodiments, the three-dimensional plane in Figure 2 can be simplified to a two-dimensional plane based on the assumption that the magnetic field is due to the current flowing through the magnet. In other words, B is I L Since it is proportionally related, a two-dimensional surface (i.e., a two-dimensional curve) can be used.

[0070]

[0077] In the embodiment, data representing Model 200 can be stored in memory 114. Model 200 can be represented as a single equation, a series of equations, a data table, a lookup table, or any type of data that can be used to represent the superconducting operation of the magnetic coil 102.

[0071]

[0078] The control circuit 101 can implement one or more control techniques for controlling the current or voltage supplied to the magnetic coil 102. Before describing examples of such techniques, some parameters of the system are described. Any of the following parameters and equations can be included in the system model used in the control circuit 101.

[0072]

[0079] System characteristics:

[0073]

[0080] t=time (measurable)

[0074]

[0081] B = magnetic field (measurable), linearly proportional to the current in the superconductor.

[0075]

[0082] T = Temperature of the magnet (measurable)

[0076]

[0083] L = Inductance of the superconducting winding of a magnet (known characteristic)

[0077]

[0084] R = Cross-turn resistance of a magnet (a known property)

[0078]

[0085] I0 = Power supply current (directly controllable)

[0079]

[0086] V0 = Power supply voltage (directly controllable)

[0080]

[0087] I L =Current in a superconductor (calculable)

[0081]

[0088] I R = Cross-turn current (calculpable)

[0082]

[0089] I C = Depends on the critical current (known properties), temperature, and magnetic field of the superconductor. Critical current I C This can be defined as the current at which a superconductor loses its superconducting properties for a given magnetic field and temperature.

[0083]

[0090] Q R = Heat generated by the magnet due to cross-turn resistance (calculable)

[0084]

[0091] Q C = Cooling power supplied to the magnet (directly controllable)

[0085]

[0092] V = Deposition of the magnet cold mass (known characteristics)

[0086]

[0093] ρ = Density of the magnet cold mass (known characteristics)

[0087]

[0094] C P = Heat capacity of the magnet cold mass (known characteristics)

[0088]

[0095] Circuit equation

[0089]

[0096] I0 = I R + I L

[0090]

[0097] V0 = V R = V L

[0091]

[0098] VR = I R R

[0092]

[0099] V L = L dI L / dt

[0093]

[0100] Heat conduction equation

[0094]

[0101] Q R = I R 2 R

[0095]

[0102] dT / dt = VρC P (Q R - Q C )

[0096]

[0103] Magnet formula

[0097]

[0104]

number

[0098]

[0105] (The proportional relationship of the magnetic field at a given position can be a complex function of the sensor position and the magnet geometry.)

[0099]

[0106] In some embodiments, the control circuit 101 can implement feedback control. One example of feedback control implementation is the inductor current I L and critical current I C Compare with I to avoid quenching C With an appropriate offset given to I C and I L The objective is to control the current and / or voltage provided by the current and / or voltage source 104 so as to minimize the difference between the two. For example, the control circuit 101 controls the current and / or voltage provided by the current and / or voltage source 104. C - Delta and I L It can be controlled to minimize the difference or "error" between and , where delta is the offset. Delta is any suitable value, for example, a fixed value or I C This refers to percentages such as 20% or less, 10% or less, 5% or less, etc. C and I L One way to compare them is, C / I L This involves calculating the value, which can then be compared to the set value. The set value can be greater than zero and less than 1 by an appropriate amount to avoid quenching. For example, the set value could be greater than or equal to 0.8, for example, greater than or equal to 0.9, for example, greater than or equal to 0.95, and less than 1. CThe relationship between the magnetic field and / or temperature can be stored by the control circuit 101. As described above, the magnetic field and / or temperature of the magnetic coil can be measured, and updates of the measured values ​​can be provided to the control circuit 101 over time. Based on the updated measured values ​​of the system (e.g., magnetic field and / or temperature), the control circuit performs the following: C The error can be recalculated periodically. Such recalculations can be performed at an appropriate rate or interval. The error can be recalculated continuously or at appropriate intervals, and the voltage and / or current provided by the voltage source 104 can be updated accordingly. Any suitable type of feedback control can be used, one example being PID control using a suitable combination of proportional, integral, and / or differential error control. However, the techniques described herein are not limited in this respect, and any of the various types of feedback control can be used.

[0100]

[0107] Another feedback control involves using a more complete model of the system. For example, a more complete model of the system may include a coupled electromagnetic and thermal model of the system. In some embodiments, future properties of the system, such as temperature, current, and critical current, can be simulated based on the measured properties of the superconducting magnet, and appropriate currents and / or voltages generated by the control circuit 101 can be determined (e.g., by direct calculation and / or optimization). The system can be resimulated at appropriate intervals during magnet charging to continuously recalculate appropriate (e.g., optimal) currents and / or voltages generated by the control circuit 101 based on updated sensor measurements.

[0101]

[0108] Referring now to Figure 3, the block diagram shows a control system 300 for controlling the magnetic coil. The control system 300 can be the same as or similar to the control system described earlier in relation to Figure 1.

[0102]

[0109] The control system 300 may include a control circuit 302 with a memory 304. In an embodiment, the memory 304 may contain data representing an operating model 305 of a magnetic coil, such as the operating model shown in Figure 2. The control circuit 302 may be coupled to a cooling control circuit 306 that controls the cooling system 308. The cooling system 308 may be the same as or similar to the cooling system described earlier in relation to Figure 1.

[0103]

[0110] The control circuit 302 can also be coupled to a current control circuit 310 that can control the current source 312. The current source 312 can be the same as or similar to the current or voltage source 104 in Figure 1. Note that in other embodiments, the current control circuit 310 can be replaced with a voltage control circuit that controls the voltage applied to the superconducting magnet.

[0104]

[0111] In one embodiment, the cooling control circuit 306, the current control circuit 310, and the control circuit 302 can be separate circuits. In another embodiment, the cooling control circuit 306, the current control circuit 310, and the control circuit 302 can be integrated into the control circuit 302.

[0105]

[0112] The magnetic field sensor 314 can measure the magnetic field around the magnetic coil and can feed back a signal 514a representing the strength of the detected magnetic field to the control circuit 302. The magnetic field sensor 314 can be the same as or similar to the magnetic field sensor 1110. The current sensor 316 can measure the value of the current flowing through the magnetic coil and can feed back a signal 516a representing the value of the current. In addition, the temperature sensor 318, which may be the same as or similar to the temperature sensor 112, can measure the temperature of the magnetic coil and can feed back a signal 518a representing the temperature to the control circuit 302.

[0106]

[0113] System 300 can provide multiple feedback loops for controlling the magnetic coil. For example, System 300 can feed back temperature information (e.g., signal 518a), current information (e.g., signal 516a), and magnetic field information (e.g., signal 514a) to Control Circuit 302. Control Circuit 302 can use these signals and Operating Model 305 to control the current and cooling of the magnetic coil, operating the magnetic coil in a way that prevents it from remaining in a superconducting state and causing a quench. Control Circuit 302 can also minimize the time the magnetic coil is supplied with energy by using these signals and Operating Model 305 to provide the maximum allowable current so that the magnetic coil remains in a superconducting state.

[0107]

[0114] In this embodiment, the control circuit 302 and / or the cooling control circuit 306 and / or the current control circuit 310 can be implemented as a state machine.

[0108]

[0115] The control system described above can be used in various embodiments, including, but not limited to, fusion power systems. For example, Figure 4 is a simplified diagram of a tokamak system 400 for generating fusion power. The diagram includes a plasma tube 402 and several superconducting magnetic coils 404-410. These coils can be the same as or similar to the magnetic coil 102 described above.

[0109]

[0116] During energy generation, a high-temperature plasma (which promotes the nuclear fusion reaction) circulates within the plasma tube 402. Because the plasma is at a very high temperature, it could destroy the plasma tube 402 if it comes into contact with its walls. Therefore, system 400 generates a magnetic field that compresses and suspends the plasma in the flow within the plasma tube 402, without contacting its walls.

[0110]

[0117] To generate a magnetic field, the tokamak system 400 has several magnetic coils 404-410. These coils may include superconducting magnets to create a magnetic field that levitates and compresses the plasma flow.

[0111]

[0118] In the embodiment, each magnetic coil 404-410 includes a series of stacked plates 412. Each stacked plate can surround a superconducting magnet made of a coil of superconducting tape material. When an electric current flows through the coil of superconducting tape, a magnetic field is generated.

[0112]

[0119] Figure 4A is a diagram of a portion 414 of the magnetic coil 410. As shown, the magnetic coil 410 may include a series of stacked plates 412. Each plate may contain a superconducting magnet, which can be in the form of a coil, such as a wound wire or tape. By driving a current through the superconducting tape, a magnetic field 416 can be generated that can compress the plasma flow 402 so that the plasma does not come into contact with the plasma tube 402.

[0113]

[0120] Referring here to Figure 5, an example of helical grooved plates stacked to form a so-called “double pancake” assembly 500 is shown. In this example, two, optionally identical, helical grooved plates 501, 502 are joined back-to-back, along with insulating material (not visible in Figure 5) inserted or positioned between them. Stacked helical grooved plate superconducting magnets and associated helical plates, which may be the same as or similar to assembly 500, are described in concurrently pending applications No. 16 / 233410 filed December 27, 2018 and No. 16 / 416781 filed May 20, 2019, each of which is incorporated herein by this reference in its entirety.

[0114]

[0121] In the exemplary embodiment shown in Figure 5, a first plate 501 is positioned on a second plate 502 so that the contact openings 504 can be aligned and used to fasten the plates together. Plate 501 includes a helical channel 506 defined by a wall 507. The channel 506 (which may also be referred to here as a grooved path or groove 506) is made to have a shape (i.e., channel length, channel width, and channel height) selected to receive the tape 508.

[0115]

[0122] Tape 508 can be provided as a high-temperature superconductor (HTS) tape stack, which may include a co-wind material inserted into grooved channels forming an inward-facing spiral on an upper plate, a spiral descending to a lower plate, and an outward-facing spiral on the lower plate. In embodiments, Tape 508 may be the same as or similar to the superconducting tapes described in concurrently pending applications No. 62 / 740163 filed 2 October 2018 and No. 16 / 416781 filed 20 May 2019, each of which is incorporated herein by this reference in its entirety.

[0116]

[0123] In some embodiments, tape 508 is wound continuously from the top to the bottom of the pancake assembly (i.e., without breaks or splits). In some embodiments, tape 508 can be non-insulated (NI) HTS tape (and, if used, a co-wind stack), which may be split or have breaks (e.g., the path of one material may be cut and not continuous). Thus, while the channel can be described as largely continuous (even if the cross-sectional shape of the channel may change throughout the length of the channel), it should be understood that the material placed on or arranged in the channel may be continuous or provided in multiple parts (e.g., split).

[0117]

[0124] In some embodiments, more than one HTS tape stack can be arranged in the groove, with material placed between the stacks, which can be mechanically engaged with the plate, individually or in relation to the tape stacks, for example, via a helical groove. In some embodiments, some or all of the materials to be wound together can be arranged to be mechanically engaged with the plate, individually or in relation to the tape stacks, for example, via a helical groove. The materials to be wound together and the surface coating can be selected to provide the desired (and ideally, optimal) magnetic quench behavior.

[0118]

[0125] Assembly 500 is suitable for use in providing a superconducting magnet assembly that can be used in any of the applications described herein.

[0119]

[0126] Similar to plate 501, plate 502 has a tape 510 arranged in its channel. In the embodiment, tape 508 and tape 510 can be electrically coupled in series to form a long winding of tape.

[0120]

[0127] In embodiments, the superconducting magnet can be configured to operate without turn-to-turn insulation. In other words, the windings of the tape 508 can be wound in overlapping directions and / or separated by a conductive material such as the material from which plates 501, 502 are provided.

[0121]

[0128] When the tape 508 exhibits superconducting properties under the conditions, its resistance to current can ideally be zero, and in any case, it can be considerably lower than the resistance of a normal conductor (a conductor that does not exhibit superconducting properties), such as the material providing plates 501, 502 (e.g., a metal). Under these conditions of relatively low voltage in the magnet, the current is mainly confined to and flows mainly through the path defined by the channel through which the tape 508 lies (i.e., the current flows through the superconductor), with a relatively small amount of current (and ideally no current) passing from winding to winding of the tape 508 (i.e., the current does not flow across the wall 507 that defines the channel through which the tapes 508, 510 lies and separate the windings of the tapes 508, 510).

[0122]

[0129] However, if conditions change and the superconducting properties are lost (all or part of them) during operation, the increased current will not flow around the coil but will flow from winding to winding of the magnet in the direction indicated by arrow 512. This phenomenon, which occurs when the tape loses its superconducting properties and the current begins to flow from winding to winding, can be called a quench.

[0123]

[0130] Referring to Figure 6, some or all of the algorithms associated with circuits 100 and 300, the cooling control circuit 306, and / or the current control circuit 310 can be implemented as software to run on a computing device such as computing device 600. Computing device 600 can be a computer, microprocessor, custom processing circuit, FPGA, or any type of circuit or computing device capable of executing software instructions.

[0124]

[0131] The computing device 600 includes a processor 602, random access memory (RAM) 604, and a storage device 606, which can be a hard drive, CD, DVD, flash drive, or any other type of non-volatile memory. Software instructions can be stored in RAM 604 and / or storage device 606. The processor 602 can be coupled to storage device 606 and / or RAM 604, thereby allowing the processor 602 to read software instructions. When the processor 602 reads software instructions, the software instructions cause the processor 602 to perform an operation to operate the magnetic coil described above in association with control circuit 302 and / or control circuit 101. Although not shown, the processor 602 and / or computing device 600 may include other inputs and / or outputs such as inputs for receiving signals from sensing elements, GPIO, power input, or other interfaces such as USB, SATA, HDMI®, etc.

[0125]

[0132] In a system with multiple superconducting magnets, numerous such systems can be coupled together.

[0126]

[0133] In embodiments, the described concept can facilitate the commercialization of high-field magnets for use in fusion power plants (e.g., compact fusion power plants) and high-energy physics applications. However, after reading the description provided herein, a person skilled in the art will readily understand that the disclosed concept is generally applicable to a wide range of other applications (e.g., a wide range of industrial applications). Such applications include, but are not limited to, applications in the fields of medicine and life sciences (e.g., magnetic resonance imaging and spectroscopy), applications in the fields of chemistry, biochemistry, and biology (e.g., nuclear magnetic resonance (NMR), NMR spectroscopy, electron paramagnetic resonance (EPR), and Fourier transform ion cyclotron resonance (FT-ICR)), applications in particle accelerators and detectors (e.g., applications in healthcare applications such as equipment for radiotherapy), applications in equipment for generating and controlling hot hydrogen plasma, applications in the field of transportation, applications in the field of power generation and conversion, applications in heavy industry, applications in weapons and defense, and applications in the field of high-energy particle physics.

[0127]

[0134] As mentioned earlier, while there have been occasional references to the use of high-field magnet assemblies in connection with fusion power plants (e.g., compact fusion power plants) and fusion research experiments (e.g., SPARC), such references are not intended to be limiting and should not be interpreted as limiting. It is understood that the control circuits and techniques provided in and for use with high-field magnet assemblies, according to the concepts described herein, will find applications in a wide variety of different applications.

[0128]

[0135] For example, in the fields of medicine and life sciences, high-field magnets provided according to the concepts described here can find applications in magnetic resonance imaging (MRI) and spectroscopy.

[0129]

[0136] Referring to Figure 7, the MRI system 700 includes a patient table 702 that guides the patient to a tube 703 defined by the MRI system 700 for scanning. The scanner 704 uses a magnet 706, a radio frequency (RF) coil 708, and a gradient coil 710 to create an image. Maintaining such a large magnetic field requires a large amount of energy, which can be achieved by using a superconducting circuit. Thus, in this embodiment, the magnet 706 may be a superconducting magnet controlled by a control circuit which may be the same as or similar to the control circuit previously described in relation to Figures 1 and 3. In this way, the MRI system 700 can be configured to use a strong magnetic field and radio waves to create detailed images of organs and tissues inside the patient's body.

[0130]

[0137] Various embodiments have been described in this patent. However, the scope of this patent should not be limited to the embodiments described, but rather should be limited only to the spirit and scope of the claims below. All references cited in this patent are incorporated as such by reference.

Claims

1. A method for controlling a superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, The physical characteristics of the superconducting magnet are perceived using a sensor, wherein the physical characteristics include temperature, voltage, current, magnetic field, and / or magnetic flux density. The method involves using a control circuit to determine electrical parameters, including current and / or voltage, for supplying power to the superconducting magnet, based on the sensed physical characteristics and a model of the superconducting magnet stored in a computer-readable storage medium, wherein the model associates the sensed physical characteristics with the critical current of the superconductor of the superconducting magnet, the critical current being the current at which the superconductor loses its superconducting properties, and the determination of the electrical parameters is made by using the model to charge the superconducting magnet with an allowable current increased to maintain the superconducting state or the maximum allowable current, thereby reducing or minimizing the charging time while avoiding overheating of the superconducting magnet to a temperature at which the superconductor loses its superconducting properties. The determined electrical parameters are provided to the superconducting magnet. A method that includes this.

2. The method according to claim 1, The physical characteristics are re-perceived after a time interval has elapsed since the perception of the physical characteristics. Using the control circuit, the electrical parameters for supplying power to the superconducting magnet are re-determined based on the re-sensed physical characteristics and the model. To provide the re-determined electrical parameters to the superconducting magnet. A method that further includes this.

3. A method according to claim 2, wherein determining includes calculating the critical current of the superconductor of the superconducting magnet, calculating the difference between the calculated current passing through the superconductor and the critical current, and comparing the difference with a set value to set the electrical parameters based on the difference.

4. A method according to claim 2, wherein determining includes calculating the critical current of the superconductor of the superconducting magnet, dividing the calculated current passing through the superconductor by the critical current to produce a ratio, comparing the ratio with a set value, and setting the electrical parameter based on the result of the comparison.

5. A method according to any one of claims 1 to 4, wherein determining comprises calculating future parameters of the superconducting magnet based on the perceived physical characteristics and the model, and setting the electrical parameters based on the calculated future parameters, wherein the calculated future parameters are temperature, current, and critical current.

6. A method according to claim 5, wherein the model includes a thermal model of the superconducting magnet.

7. A method according to any one of claims 1 to 6, further comprising determining a degree of cooling based on the model and the sensed physical characteristics, and controlling a cooling system for the superconducting magnet based on the determined degree of cooling.

8. A device for controlling a superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, Including a control circuit, the control circuit is Receiving the sensed physical characteristics of the superconducting magnet from the sensor, wherein the physical characteristics include temperature, voltage, current, magnetic field, and / or magnetic flux density. The method involves determining electrical parameters, including current and / or voltage, for supplying power to the superconducting magnet, based on the perceived physical characteristics and a model of the superconducting magnet stored in a computer-readable storage medium, wherein the model associates the perceived physical characteristics with the critical current of the superconductor of the superconducting magnet, the critical current being the current at which the superconductor loses its superconducting properties, and the determination of the electrical parameters is made by using the model to charge the superconducting magnet with an allowable current increased to maintain the superconducting state or the maximum allowable current, thereby reducing or minimizing the charging time while avoiding overheating of the superconducting magnet to a temperature exceeding the temperature at which the superconductor loses its superconducting properties. The determined electrical parameters are provided to the superconducting magnet. A device configured to perform the following actions.

9. The apparatus according to claim 8, wherein the control circuit further comprises After a time interval has elapsed since the initial sensing of the aforementioned physical features, the resensing physical features are received. Based on the re-perceived physical characteristics and the model, the electrical parameters for supplying the superconducting magnet are re-determined. The re-determined electrical parameters are provided to the superconducting magnet. A device configured in such a way.

10. The apparatus according to claim 9, wherein the control circuit is configured to calculate the critical current of the superconductor of the superconducting magnet, calculate the difference between the calculated current passing through the superconductor and the critical current, and determine the electrical parameters by comparing the difference with a set value and setting the electrical parameters based on the difference.

11. The apparatus according to claim 9, wherein the control circuit is configured to calculate the critical current of the superconductor of the superconducting magnet, divide the calculated current passing through the superconductor by the critical current to create a ratio, compare the ratio with a set value, and determine the electrical parameters by setting the electrical parameters based on the result of the comparison.

12. An apparatus according to any one of claims 8 to 11, wherein the control circuit is configured to determine the electrical parameters by calculating the future parameters of the superconducting magnet based on the sensed physical characteristics and setting the electrical parameters based on the calculated future parameters, wherein the calculated future parameters are temperature, current, and critical current.

13. The apparatus according to claim 12, wherein the model includes a thermal model of the superconducting magnet.

14. An apparatus according to any one of claims 8 to 13, wherein the control circuit is configured to determine a degree of cooling based on the model and the sensed physical characteristics, and to control a cooling system for the superconducting magnet based on the determined degree of cooling.

15. It is a system, A superconducting magnet having no or partial electrical insulation between each winding of the superconducting magnet, The apparatus according to any one of claims 8 to 14 and A system that includes this.

16. It is a system, A superconducting magnet comprising a coil of superconducting material including two electrical terminals, wherein the windings of the coil are separated by a metal conductor, An apparatus according to any one of claims 8 to 14, wherein the control circuit in the apparatus is coupled to the two terminals to drive a current through a coil for charging the superconducting magnet, and is configured to provide through the coil a current that is small enough to avoid the quench effect of the superconducting magnet and large enough to charge the magnet within a predetermined period of time, A cooling structure that is thermally coupled to a coil to remove the heat generated by the charging of the superconducting magnet by the current, and that allows the current to be large enough to charge the magnet within the predetermined period without causing the quench effect. A system that includes this.

17. The system according to claim 16, wherein the cooling structure is configured to maintain the temperature of the coil at 4K or higher.

18. The system according to claim 16, wherein the control circuit further includes one or more feedback loops.

19. The system according to claim 18, wherein the one or more feedback loops feed back the temperature of the coil.

20. The system according to claim 18, wherein the one or more feedback loops feed back the current passing through the coil.

21. The system according to claim 18, wherein the one or more feedback loops feed back the magnetic field of the coil.

22. A system according to claim 16, wherein the model includes a temperature limit for the coil, a current limit for the coil, and a magnetic field limit for the coil.

23. The system according to claim 22, wherein the temperature limit, the current limit, and the magnetic field limit define the range in which the coil acts as a superconductor.

24. A method for controlling a superconducting magnetic coil, The variable current supply source drives the current passing through the superconducting magnetic coil, The control circuit uses sensors to monitor the current flowing through the superconducting magnetic coil, the temperature of the superconducting magnetic coil, and the magnetic field around the superconducting magnetic coil. The control circuit determines the operating point of the superconducting magnetic coil by comparing the temperature, current, and magnetic field with a model of the superconducting magnetic coil stored in the control circuit, which defines the operating range in which the coil acts as a superconductor, wherein the model associates the temperature, current, and magnetic field with the critical current of the superconductor of the superconducting magnetic coil, and the critical current is the current at which the superconductor loses its superconducting properties, and when determining the operating point, the model is used to charge the superconducting magnetic coil with an allowable current increased to the point at which the superconductor remains in a superconducting state, or the maximum allowable current, thereby reducing or minimizing the charging time while avoiding overheating of the superconducting magnetic coil to a temperature at which the superconductor loses its superconducting properties, Based on the operating point and operating range of the superconducting magnetic coil, the maximum current available for charging the coil is determined. To supply energy to the superconducting magnetic coil, the current is adjusted to match the maximum current. A method that includes this.

25. A method according to claim 24, wherein the control circuit controls a cooling system to cool the superconducting magnetic coil when the maximum current is applied so that the superconducting magnetic coil remains within the operating range.

26. A method according to claim 25, wherein the cooling system is configured to maintain the temperature of the coil at 4K or higher.

27. A method according to claim 24, wherein the control circuit further comprises one or more feedback loops.

28. A method according to claim 27, wherein the one or more feedback loops feed back the temperature of the coil.

29. A method according to claim 27, wherein the one or more feedback loops feed back the current passing through the coil.

30. A method according to claim 27, wherein the one or more feedback loops feed back the magnetic field of the coil.

31. A method according to claim 24, wherein the model includes a temperature limit for the coil, a current limit for the coil, and a magnetic field limit for the coil.

32. A method according to claim 31, wherein the temperature limit, the current limit, and the magnetic field limit define the range in which the coil acts as a superconductor.

33. A method according to claim 24, wherein the windings of the superconducting magnetic coil are separated by a metal conductor.

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