CN101521078A - Superconducting magnet with quench protection circuit - Google Patents
Superconducting magnet with quench protection circuit Download PDFInfo
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- CN101521078A CN101521078A CN200810232384A CN200810232384A CN101521078A CN 101521078 A CN101521078 A CN 101521078A CN 200810232384 A CN200810232384 A CN 200810232384A CN 200810232384 A CN200810232384 A CN 200810232384A CN 101521078 A CN101521078 A CN 101521078A
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Abstract
The invention discloses a superconducting magnet quench protection circuit and a superconducting magnet with the same. The superconducting magnet quench protection circuit comprises a diode, an insulated-gate bipolar transistor and an energy leakage resistor, and the diode is serially connected with the insulated-gate bipolar transistor and then is parallelly connected with the energy leakage resistor; and the superconducting magnet comprises a body of the superconducting magnet, and is assembled with the superconducting magnet quench protection circuit, a quench detector, a current sensor, a short circuiter, and a current injection conductor. The protection circuit provides active quench protection for the superconducting magnet, and has sensitive quench judgment, and most of heat produced during the quench is dissipated on the energy leakage resistor outside the superconducting magnet so as to prevent the quick change of heat stress produced by a heater from causing the damage to the mechanical property of a superconductor, and prolong the service life of a superconducting line. The heat load of a cooling system produced during the quench is also greatly reduced, the time for returning to a superconducting state through the re-cooling after the quench is shortened, and the work efficiency of the whole machine is improved.
Description
Technical field
The present invention relates to a kind of superconducting magnet, particularly a kind of superconducting magnet that has based on the quench protection arrangement of big capacity IGBT (Insulated-Gate Bipolar Transistor, igbt).
Background technology
Flourish along with superconductor technology and superconductor, superconducting magnet has wide application prospect.Because the superconducting magnet volume is little, current density is high, energy consumption is low, the field intensity advantages of higher, is more and more adopted at key areas such as basic scientific research, health care, communications and transportation, national defense industry in recent years.When the superconductor that is used for superconducting magnet is returned to resistance states, be referred to as quench (Quench).This may be that certain parameter such as density owing to the intensity of temperature, external magnetic field or loaded current exceeds its critical value and causes.The sub-fraction of superconductor no longer is superconduction, but enters resistance states, and the electric current of any this active component of flowing through all can cause the local joule heating.This will cause the neighbouring part quench of this superconductor, and the result forms bigger Resistance states volume, and this causes joule heating further again.Soon, superconductor enters resistance states, if at this moment also have bigger electric current still at this superconductor of flowing through, that is breakneck, can damage superconductor in a flash.
In the practical application, before quench, superconducting magnet generally can have may be the storage power of the megajoule order of magnitude.After quench, energy storage will be consumed in the Resistance states volume of conductor.If control the quench process inadequately, will be in limited this energy storage of regional internal consumption, thus cause local temperature to rise, this local temperature rising can damage on the part that quench begins or near coil region.
Known can concentrating by the heat that expansion quench process is avoided being harmful to, this just need control the quench process rightly, is also referred to as superconducting magnet is carried out quench protection.The effect of this quench protection mainly is when magnet generation quench, and the hot(test)-spot temperature of coil is controlled in the safe range.The essence of control hot(test)-spot temperature is exactly the deposition of control energy storage at focus, concentrate by the heat that expansion quench process is avoided being harmful to, so that the heat that on available superconductor as much as possible, dissipates and produced, the quench that this will cause relating to basically whole superconductor means that arbitrary part should not reach dangerous temperature.Generally be that this heating element and coil have thermo-contact closely, realize deliberate quench by apply electric current to heating element for each superconducting coil is equipped with heating element.
The quench protection of superconducting magnet mainly relies on the protective circuit of design to be the passive protection circuit at present; for superconducting magnet provides passive protection; when quench takes place; realize deliberate quench by apply electric current to heating element; concentrate with the heat that expansion quench process is avoided being harmful to; allow energy storage be converted into heat uniformly on available superconductor as much as possible and dissipate, this will cause relating to basically the quench of whole superconductor.Because the finite energy that passive protection shifts so be adapted to bigger, the passive superconducting coil of copper hypergeometric (ratio of the content of copper and superconductor in the superconducting line) more.
Existing protector or protective circuit have significant disadvantages: one, and the most heats that produce in the quench process all are dissipated in the superconductor, and the quick variation meeting of thermal stress damages the mechanical performance of superconductor.For most of superconductors, when temperature surpassed 100K, the deformation meeting that thermal expansion causes was apparent in view.Too high temperature can make superconducting line degenerate, and causes critical current reduction etc.High temperature also can damage the outer field insulating material of superconducting line.Its two, superconductor generally all is operated in the low temperature about 10K, uses heating element can increase the heat load of cooling system greatly, prolongs the time that enters superconducting state after the quench once more, reduces the operating efficiency of whole machine.
Summary of the invention
Purpose of the present invention is exactly to eliminate the deficiency and the shortcoming of technique scheme, designs a kind ofly to have that response is fast, the life-span long, control is sensitive, volume is little, the superconducting magnet of the quench protection arrangement of dependable performance.
In order to achieve the above object; the invention provides a kind of superconducting magnet quench protection circuit and the superconducting magnet that has this protective circuit; described superconducting magnet quench protection circuit comprises diode, igbt and lets out can resistance, described diode with after igbt is connected again with to let out energy resistance in parallel.
Described superconducting magnet; comprise at least six series connection superconducting coil superconducting magnet bodies that L1 ~ L6 forms; be equipped with the above-mentioned superconducting magnet quench protection circuit of stating; the quench detector; current sensor; short-circuiting device and electric current inject lead; superconducting magnet body one end in the described superconducting magnet is connected to an end of short-circuiting device by current sensor; the superconducting magnet body other end connects an end of quench protection arrangement; the other end of quench protection arrangement connects the other end of short-circuiting device; electric current injects the two ends that lead connects short-circuiting device; each end points of described series coil all connects with the quench detector; the quench detector connects with current sensor, and the quench detector connects with igbt.
Beneficial effect of the present invention:
1.. for superconducting magnet provides initiatively quench protection.Detect the generation of quench at first accurately, implement predetermined protection action by protective circuit again.For the superconducting magnet that energy storage is big, the copper hypergeometric is little, the superconducting line cross section is little, use is initiatively protected safer, reasonable, also is convenient to most energy are transferred to outside letting out on the energy resistance, and the hot(test)-spot temperature after the control quench is in permissible value.
2.. quench protection is judged very sensitive, and the most heats that produce in the quench process all be dissipated in letting out of superconducting magnet outside can resistance on, the quick variation of having avoided the thermal stress that heating element produces damages the mechanical performance of superconductor.The temperature of superconducting magnet only has very little rising (because wherein the heat that dissipates is very little), and this is highly beneficial to the outer field insulating material of superconducting line, and the superconducting line of also having avoided high temperature to cause is degenerated, and has prolonged the useful life of superconducting line.Certainly the heat load of the cooling system that produces in the quench process also is greatly reduced, and the time that is cooled to superconducting state after the quench once more is shortened, and has improved the operating efficiency of whole machine.
Description of drawings
Fig. 1 is a circuit diagram of the present invention
Embodiment
The invention provides a kind of superconducting magnet quench protection circuit 1 and the superconducting magnet 10 that has this protective circuit 1 as shown in Figure 1; described superconducting magnet quench protection circuit 1 comprises diode 2, igbt 3 and lets out can resistance 4, described diode 2 with after igbt 3 is connected again with to let out energy resistance 4 in parallel.
Described superconducting magnet 10; comprise at least six series connection superconducting coil superconducting magnet bodies 5 that L1 ~ L6 forms; be equipped with above-mentioned superconducting magnet quench protection circuit 1; quench detector 6; current sensor 7; short-circuiting device 8 and electric current inject lead 9; superconducting magnet body 5 one ends in the described superconducting magnet 10 are connected to an end of short-circuiting device 8 by current sensor 7; superconducting magnet body 5 other ends connect an end of quench protection arrangement 1; the other end of quench protection arrangement 1 connects the other end of short-circuiting device 8; electric current injects the two ends that lead 9 connects short-circuiting device 8; each end points of described series coil all connects with quench detector 6; quench detector 6 connects with current sensor 7, and quench detector 6 connects with igbt 3.
In the operate as normal; when whole system is connected to external power source by electric current injection lead 9; electric current will be mainly by igbt in the quench protection arrangement 13 and the diode 2 superconducting magnet body 5 of flowing through; let out and to have only very little electric current process in the resistance 4, and short-circuiting device 8 disconnects.The current signal i of voltage and current transducer 7 outputs of each end points of quench detector 6 collection superconducting coil L1~L6
m, this voltage of computational analysis, electric current and Ldi/dt signal and correlation thereof.Compare with the calculated value of superconducting coil L1~L6 when the engineering design then, thereby whether analysis and judgement superconducting coil L1~L6 is operated in superconducting state.If at superconducting state, then electric current will be mainly by igbt in the quench protection arrangement 13 and the diode 2 superconducting coil L1~L6 that flows through.In case quench takes place in the somewhere among superconducting coil L1~L6, can be judged the output signal u of quench detector 6 by quench detector 6 at once
cIgbt 3 will be turn-offed, and external power source also is turned off short-circuiting device 8 conductings simultaneously.The flow through current i of superconducting coil L1~L6
dBy short-circuiting device 8, let out and can resistance 4 continue to flow.Owing to let out can resistance 4 resistance value partly to be the resistance value that Resistance states occurs than quench in the superconducting coil many greatly, let out and can generate heat fast by resistance 4 so the electric current that continues to flow will make, this electric current is also decayed fast simultaneously.So also just make a large amount of superconducting magnet energy storage be converted into heat, and shifted, no longer be dissipated in the superconducting coil, let out on the energy resistance 4 but be dissipated in.This is extraordinary to superconducting coil, helps the safe and stable operation of superconducting coil.
This quench protection is called as initiatively quench protection.At first to detect the generation of quench accurately, implement predetermined protection action by protective circuit again.For the superconducting magnet that energy storage is big, the copper hypergeometric is little, the superconducting line cross section is little, use is initiatively protected safer, reasonable, also is convenient to most energy are transferred to outside letting out on the energy resistance, and the hot(test)-spot temperature after the control quench is in permissible value.
The present invention needs the injection current application scenario opposite with the id direction when working for superconducting magnet, only need in quench protection arrangement 1 one be parallel to diode 2, diode, igbt series arm that igbt 3 directions are opposite to let out energy resistance 4 two ends and can realize quench protection under this occasion.
Advantage of the present invention is that the quench judgement is very sensitive, and the most heats that produce in the quench process All be dissipated in letting out on the energy resistance of superconducting magnet outside, avoided the quick change of the thermal stress of heating element generation Change damages the mechanical performance of superconductor. The temperature of superconducting magnet only has very little rising (because wherein The heat that dissipates is very little), this is highly beneficial to the outer field insulating materials of superconducting line, has also avoided high temperature to cause Superconducting line degenerate, prolonged the service life of superconducting line. Certainly the cooling system that produces in the quench process Thermic load also is greatly reduced, and the time that again is cooled to superconducting state after the quench is shortened, and has improved integral body The operating efficiency of machine.
Claims (2)
1. a superconducting magnet quench protection circuit (1); it is characterized in that: described magnet quench protection arrangement (1) comprises diode (2), igbt (3) and lets out can resistance (4), described diode (2) with after igbt (3) is connected again with to let out energy resistance (4) in parallel.
2. a superconducting magnet (10); comprise at least six series connection superconducting coil superconducting magnet bodies (5) that L1~L6 forms; it is characterized in that: described superconducting magnet (10) is equipped with the described superconducting magnet quench protection circuit of claim 1 (1); quench detector (6); current sensor (7); short-circuiting device (8) and electric current inject lead (9); superconducting magnet body (5) one ends in the described superconducting magnet (10) are connected to an end of short-circuiting device (8) by current sensor (7); superconducting magnet body (5) other end connects an end of quench protection arrangement (1); the other end of quench protection arrangement (1) connects the other end of short-circuiting device (8); electric current injects the two ends that lead (9) connects short-circuiting device (8); each end points of described series coil all connects with quench detector (6); quench detector (6) connects with current sensor (7), and quench detector (6) connects with igbt (3).
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN106098291A (en) * | 2016-07-29 | 2016-11-09 | 中国原子能科学研究院 | The quick demagnetizing method of cyclotron big energy storage superconducting coil |
CN109510167A (en) * | 2018-11-13 | 2019-03-22 | 中国原子能科学研究院 | A kind of compact superconducting cyclotron based on cascade quenches protection circuit |
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CN2267571Y (en) * | 1996-04-30 | 1997-11-12 | 陈寄炎 | Loss-free and resistor type arrangement for limiting excess current at short-circuit emergency |
CN1391324A (en) * | 2002-06-27 | 2003-01-15 | 浙江大学 | Current limiter with by-pass inductor for short-circuit failure |
CN1756021A (en) * | 2004-09-28 | 2006-04-05 | 中国科学院电工研究所 | A kind of short-circuit fault current limiter |
GB2422958B (en) * | 2005-02-04 | 2008-07-09 | Siemens Magnet Technology Ltd | Quench protection circuit for a superconducting magnet |
CN1874102A (en) * | 2005-06-01 | 2006-12-06 | 中国科学院电工研究所 | Low temperature bridge circuit type superconducting fault current limiter |
CN1901311A (en) * | 2006-07-19 | 2007-01-24 | 中国科学院等离子体物理研究所 | High power abnormal and over protective switch based on thyrister |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN106098291A (en) * | 2016-07-29 | 2016-11-09 | 中国原子能科学研究院 | The quick demagnetizing method of cyclotron big energy storage superconducting coil |
CN109510167A (en) * | 2018-11-13 | 2019-03-22 | 中国原子能科学研究院 | A kind of compact superconducting cyclotron based on cascade quenches protection circuit |
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