An energy recovery accelerator superconducting diode iron quench protection circuit

Abstract

The present invention discloses an energy recovery accelerator superconducting diode iron quench protection circuit, comprising: a superconducting coil L, a heater protection circuit connected in parallel to the superconducting coil L, a thermoelectric generator TEG arranged in parallel on the superconducting coil L, an energy storage battery BAT connected in series to the thermoelectric generator TEG, a double-throw switch S2 connected in series to the thermoelectric generator TEG, and a contact 2 of the double-throw switch S2 connects the energy storage battery BAT in series to the thermoelectric generator TEG, and a contact 1 of the double-throw switch S2 connects the energy storage battery BAT in series to the superconducting coil L. The present invention recovers the energy released by the superconducting coil during quenching through the TEG device and stores it in the energy storage battery, and uses the energy of the energy storage battery to supply energy for the next excitation, thereby realizing energy recycling.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting accelerators, and in particular to an accelerator superconducting diode iron quench protection circuit with energy recovery. Background Art

[0002] Under certain conditions, such as appropriate temperature, magnetic field and current density, superconducting coils will show remarkable superconducting properties, which makes them have broad application prospects in many fields such as power transmission, maglev trains, and nuclear magnetic resonance imaging. However, when these specific operating conditions are destroyed, the superconducting coil will quench. When the superconducting coil occurs, the superconducting coil will lose its superconducting state and turn into an ordinary conductor, thereby generating a large amount of Joule heat. The accumulation of this heat will cause the local temperature of the superconducting accelerator to be too high, and there is a risk of burning the accelerator diode. At the same time, the high voltage generated at the moment of quenching may break through the inter-turn and inter-layer insulation of the accelerator diode, generate arcs, and further damage the superconducting accelerator. In addition, the generation of a large amount of Joule heat will also cause the liquid helium used to cool the accelerator superconducting diode to quickly vaporize, which will cause the internal pressure of the thermostat to increase, posing a threat to the accelerator equipment and the thermostat itself. These phenomena and consequences are all due to the energy release and state transition after the superconducting coil is quenched.

[0003] Among them, the active protection circuit can timely detect and determine whether the superconducting diode is quenched by real-time monitoring of the voltage and current signals of the superconducting coil. Once the quench signal is detected, the active protection circuit will quickly take measures, such as disconnecting the power supply and connecting the superconducting diode to the energy discharge resistor to discharge the superconducting diode energy; or accelerating the superconducting diode quench through an external heater to avoid local overheating of the superconducting diode. The passive protection circuit does not rely on the detection of the voltage and current signals of the superconducting diode. It consumes the energy of the superconducting diode inside it through resistors, diodes and other devices connected in parallel with the superconducting coil, thereby realizing the protection of the superconducting diode. Active protection and passive protection each have their own advantages and disadvantages. The former can accurately control the quench process, but the cost is relatively high; the latter has a simple structure and is easy to implement, but its scope of application is limited.

[0004] Although the active protection circuit can accurately control the quench process, the signal processing system used to generate and detect the quench signal will greatly increase the cost of the protection system. This is undoubtedly a considerable burden for application scenarios that require large-scale deployment of superconducting coils. Secondly, although the passive protection circuit is simple in structure and easy to implement, it is mainly suitable for superconducting diodes with low current density and low energy storage. For large superconducting coils, passive protection may not provide sufficient protection. In addition, whether it is active protection or passive protection, the existing technology does not consider the recycling method of superconducting diode energy. When the superconducting coil is quenched, a large amount of energy stored in the superconducting diode is wasted, which not only causes a waste of energy, but also may have adverse effects on the surrounding environment. Summary of the invention

[0005] The embodiment of the present invention provides an accelerator superconducting diode quench protection circuit for energy recovery, which is used to solve the problem that the prior art does not consider the method of recycling the energy of the superconducting diode. When the superconducting coil quenches, the energy stored in the superconducting diode is wasted, which may have an adverse effect on the surrounding environment.

[0006] On the one hand, an embodiment of the present invention provides an accelerator superconducting diode iron quench protection circuit for energy recovery, comprising:

[0007] A superconducting coil L, a heater protection circuit is connected in parallel to the superconducting coil L, a thermoelectric power generation device TEG is arranged in parallel on the superconducting coil L, the thermoelectric power generation device TEG is connected in series with an energy storage battery BAT, the thermoelectric power generation device TEG is connected in series with a double-throw switch S2, contact 2 of the double-throw switch S2 connects the energy storage battery BAT in series to the thermoelectric power generation device TEG, and contact 1 of the double-throw switch S2 connects the energy storage battery BAT in series to the superconducting coil L.

[0008] In a possible implementation, the superconducting coil L is connected in series with an excitation power source E, and a switch S1 is provided between the excitation power source E and the superconducting coil L.

[0009] In a possible implementation, a protection circuit is connected in parallel to the excitation power source E. The protection circuit includes a superconducting switch R and a diode group D1 connected in parallel to the excitation power source E. Two diodes of the diode group D1 are connected in anti-parallel.

[0010] In a possible implementation, a plurality of superconducting coils L are provided, and the plurality of superconducting coils L are arranged in series. The thermoelectric power generation devices TEG are arranged corresponding to the positions of the plurality of superconducting coils L, and the plurality of thermoelectric power generation devices TEG are arranged in series.

[0011] In a possible implementation, the heater protection circuit includes a resistor R1 and a diode group D2, and the heater protection circuit of the superconducting coil L close to the switch S1 is further connected in series with a heater H.

[0012] In a possible implementation, a plurality of the heaters H are provided, and the plurality of heaters H are arranged in series.

[0013] In a possible implementation, the heaters H are arranged corresponding to the number and positions of the superconducting coils L.

[0014] In a possible implementation, the two diodes in the diode group D2 are connected in reverse parallel.

[0015] The energy recovery superconducting MRI quench protection circuit of the present invention has the following advantages:

[0016] The TEG device is used to recover the energy released by the superconducting diode iron during timeout and store it in the energy storage battery. The energy of the energy storage battery is used to provide energy for the next excitation, thus realizing the recycling of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of an accelerator superconducting diode quench protection circuit for energy recovery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Figure 1 A schematic diagram of an accelerator superconducting diode iron quench protection circuit for energy recovery provided in an embodiment of the present invention; an accelerator superconducting diode iron quench protection circuit for energy recovery provided in an embodiment of the present invention comprises:

[0021] A superconducting coil L, a heater protection circuit is connected in parallel to the superconducting coil L, a thermoelectric power generation device TEG is arranged in parallel on the superconducting coil L, the thermoelectric power generation device TEG is connected in series with an energy storage battery BAT, the thermoelectric power generation device TEG is connected in series with a double-throw switch S2, contact 2 of the double-throw switch S2 connects the energy storage battery BAT in series to the thermoelectric power generation device TEG, contact 1 of the double-throw switch S2 connects the energy storage battery BAT in series to the superconducting coil L, the superconducting coil L is connected in series with an excitation power supply E, and a switch S1 is arranged between the excitation power supply E and the superconducting coil L.

[0022] Exemplarily, when a quench occurs, the superconducting coil L generates a large amount of Joule heat. While heating the heater H, the heat generated also causes a temperature difference on both sides of the thermoelectric generator TEG. Using the Seebeck effect, the thermoelectric generator TEG converts thermal energy into electrical energy and stores it in the energy storage battery BAT. During the next excitation, the energy of the energy storage battery BAT is first used for excitation, and then the excitation power supply E is used for conventional excitation. When the double-throw switch S2 contacts contact 2, the energy storage battery BAT is connected in series to the thermoelectric generator TEG to charge the energy storage battery BAT. When the double-throw switch S2 contacts contact 1, the energy storage battery BAT is connected in series to the superconducting coil L to form an excitation circuit. The switch S1 is connected in series with the excitation power supply E to turn on and off the excitation power supply.

[0023] The overall circuit working state is divided into four stages:

[0024] In the first stage, the accelerator superconducting dipole iron power supply is excited:

[0025] The switch S1 is closed, the switch S2 is opened, and the excitation power supply E generates an excitation current to normally excite the superconducting coil L.

[0026] The second stage, normal work:

[0027] After the superconducting diode is magnetized, the switch S1 is turned off, the switch S2 is turned off, the superconducting switch R is turned on in the superconducting state, and the current flows between the superconducting coil L and the superconducting switch R in a closed loop.

[0028] The third stage, quench protection:

[0029] When the superconducting coil L is partially quenched, switch S1 is disconnected and switch S2 is placed at contact 2. At this time, the current flowing through the superconducting coil L is bypassed by the protection resistor R1 and the diode group D2, and flows through the heater H. Since the heaters H of the segmented coils are connected in series, when a local quench occurs, all heaters work synchronously, accelerating the quench progress of the entire system. At the same time, the quenched superconducting coil L will cause the local ambient temperature to rise, and the thermoelectric power generation device TEG is used to convert thermal energy into electrical energy and store it in the energy storage battery BAT.

[0030] The fourth stage, energy storage battery excitation:

[0031] The superconducting coil L is re-excited after losing superconductivity, and the energy stored in the energy storage battery BAT is first used. At this time, the switch S1 is disconnected, and the switch S2 is set to the 1 contact. The excitation current in the energy storage battery BAT excites the superconducting coil L. After the energy storage battery BAT is discharged, the superconducting diode iron power supply excitation stage is restored.

[0032] In a possible embodiment, a protection circuit is connected in parallel to the excitation power source E. The protection circuit includes a superconducting switch R and a diode group D1 connected in parallel to the excitation power source E. Two diodes of the diode group D1 are connected in anti-parallel.

[0033] Exemplarily, the superconducting switch R is used to open and close the branch where it is located. When excitation occurs, the superconducting switch R loses superconductivity and its branch is in an open state. When the excitation ends, the superconducting switch closes, and the superconducting coil L forms a closed loop and starts to work normally. The diode group D1 is used to clamp the voltage generated on the superconducting coil L at the moment when the superconducting MRI equipment loses superconductivity, thereby protecting the superconducting coil L.

[0034] In a possible embodiment, a plurality of the superconducting coils L are provided, and the plurality of the superconducting coils L are arranged in series. The thermoelectric power generation devices TEG are arranged corresponding to the positions of the plurality of superconducting coils L, and the plurality of the thermoelectric power generation devices TEG are arranged in series.

[0035] In a possible embodiment, the heater protection circuit includes a resistor R1 and a diode group D2. The heater protection circuit of the superconducting coil L near the switch S1 is also connected in series with a heater H. A plurality of heaters H are provided. The plurality of heaters H are arranged in series. The heaters H are arranged corresponding to the number and position of the superconducting coils L. The two diodes of the diode group D2 are arranged in reverse parallel.

[0036] Exemplarily, H is a heater. Since each segment of the heater H is connected in series, when the superconducting coil L is partially quenched, the current flowing through the remaining heaters can accelerate the overall quench process and avoid overheating and overvoltage hazards of the superconducting MRI equipment; the diode group D2 connected in parallel to each group of segmented superconducting coils L is used to isolate the inductive voltage during the excitation process, prevent the current from flowing through the resistor R1, and prevent the heater H from malfunctioning. The resistor R1 connected in parallel to each group of segmented superconducting coils L is the protection resistor of the diode group D2, which is used to reduce the conduction current of the diode group D2 and avoid overstress problems.

[0037] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0038] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An energy recovery accelerator superconducting diode iron quench protection circuit, characterized in that: include: A superconducting coil L, a heater protection circuit is connected in parallel to the superconducting coil L, a thermoelectric generator TEG is arranged in parallel to the superconducting coil L, the thermoelectric generator TEG is connected in series with an energy storage battery BAT, the thermoelectric generator TEG is connected in series with a double-throw switch S2, a contact 2 of the double-throw switch S2 connects the energy storage battery BAT in series to the thermoelectric generator TEG, and a contact 1 of the double-throw switch S2 connects the energy storage battery BAT in series to the superconducting coil L; The superconducting coil L is connected in series with an excitation power supply E, and a switch S1 is provided between the excitation power supply E and the superconducting coil L; A protection circuit is connected in parallel to the excitation power supply E, and the protection circuit includes a superconducting switch R and a diode group D1 connected in parallel to the excitation power supply E, and two diodes of the diode group D1 are arranged in reverse parallel; The superconducting coils L are provided in plurality, and the plurality of superconducting coils L are arranged in series. The thermoelectric power generation devices TEG are arranged corresponding to the positions of the plurality of superconducting coils L, and the plurality of thermoelectric power generation devices TEG are arranged in series.

2. The accelerator superconducting diode quench protection circuit for energy recovery according to claim 1, characterized in that: The heater protection circuit includes a resistor R1 and a diode group D2. The heater protection circuit of the superconducting coil L near the switch S1 is further connected in series with a heater H.

3. The accelerator superconducting diode quench protection circuit for energy recovery according to claim 2, characterized in that: A plurality of heaters H are provided, and the plurality of heaters H are arranged in series.

4. The accelerator superconducting diode quench protection circuit for energy recovery according to claim 3, characterized in that: The heaters H are arranged corresponding to the number and position of the superconducting coils L.

5. The accelerator superconducting diode quench protection circuit for energy recovery according to claim 2, characterized in that: The two diodes of the diode group D2 are connected in reverse parallel.

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