A performance test system for superconducting quench protection circuit in liquid helium temperature range

Abstract

The invention discloses a performance test system for a superconducting quench protection circuit in a liquid helium temperature zone, comprising a low-temperature purified helium device, a programmable power supply, a PLC logic control unit, and a workstation computer; a temperature sensor and a pressure gauge on the low-temperature purified helium device are connected to the workstation computer through a data acquisition bus, the workstation computer is connected to the programmable power supply and the PLC logic control unit, and both the programmable power supply and the PLC logic control unit are connected to a superconducting quench protection circuit sample in the low-temperature purified helium device through a relay group; a plurality of superconducting quench protection circuit samples are inserted into the low-temperature purified helium device, data collected by sensors in the low-temperature purified helium device are transmitted to the workstation computer through the data acquisition bus, and whether a test environment reaches a set condition is judged through an MCGS program set in the workstation computer; the workstation computer transmits instructions to the PLC logic control unit and transmits a set program to the programmable power supply; and the PLC logic control unit controls the relay group.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting magnets, and in particular relates to a performance testing system for a superconducting quench protection circuit in a liquid helium temperature region. Background Art

[0002] Superconducting magnets are devices made of superconducting materials wound into coils to generate strong magnetic fields or store energy. They are specifically composed of superconducting coils, support structures, refrigeration structures, etc. Since the first superconducting magnet was realized in 1961, the development of superconducting magnets has been very rapid. Currently, there are thousands of superconducting magnets in operation, with apertures ranging from small magnets of a few centimeters to large magnets of 5 meters; magnetic field strengths range from a few Teslas to tens of Teslas, and weights range from a few tenths of a kilogram to hundreds of tons.

[0003] In order to quickly extract the energy stored in the superconducting magnet without damaging the superconducting magnet in the event of a quench, a logic judgment circuit is often connected in parallel at both ends of the magnet to form a judgment of the quench situation, and then the large current in the superconducting magnet is extracted from the bypass, thereby providing protection for the quenched magnet. However, if the superconducting magnet quench protection circuit is placed in a room temperature environment, a large amount of lead loss will inevitably occur, and the superconducting magnet quench protection circuit also needs to work in a low-temperature environment. The low-temperature characteristics of superconducting magnet quench protection circuit products usually lack consistency, and the electrical performance of the superconducting magnet quench protection circuit in the liquid helium temperature zone needs to be tested. If the needs of industrial mass production are to be met, it is necessary to develop a set of equipment that can realize controllable logic batch testing of the electrical performance of the superconducting magnet quench protection circuit in the liquid helium temperature zone.

[0004] At present, the research on parameter measurement technology and equipment at low temperatures in superconducting applications mainly focuses on the measurement of various physical properties of materials. Its main purpose is still for scientific research and is not suitable for the needs of industrial production.

[0005] The research on low-temperature measurement devices is mainly aimed at the measurement of thermal, mechanical and electromagnetic properties of materials for scientific research purposes. For example, PPMS is only suitable for laboratory scientific research. The number and types of sample loading for each test are limited, the cooling time is long, and the operation is complicated. Many of the above-mentioned measurement devices are based on GM refrigerators, which have small cooling capacity and long cooling cycle. Each sample clamping and cooling takes a lot of time, and they do not have the functions of automatic, editable, input of multiple variables, and batch detection. The quench protection circuit of low-temperature superconducting magnets in superconducting magnets plays a very important role in the safety of magnets. Currently, the publicly published literature has only studied the volt-ampere characteristics of the superconducting magnet quench protection circuit in the 77K temperature zone. Based on the fact that superconducting magnets are usually cooled by liquid helium immersion and work in the 4K temperature zone, the quench protection circuit of superconducting magnets is usually pre-buried in the magnet and also works in the 4K liquid helium temperature zone. If a fault occurs, it is very troublesome to replace it, and the magnet needs to be disassembled completely. The use of liquid helium is also filled once and then released into the atmosphere. Therefore, in the large-scale MRI production process, the superconducting magnet quench protection circuit must be tested in the 4K temperature range, but there is currently no test equipment for batch automated screening of superconducting magnet quench protection circuits. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a performance test system for a superconducting quench protection circuit in a liquid helium temperature range, which can solve the shortcomings of the existing engineering research and development stage, such as lack of actual multi-variable input, multi-result collection, and logical judgment and analysis of the performance of the superconducting quench protection circuit by output variables.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A performance test system for a superconducting quench protection circuit in a liquid helium temperature range, comprising a low-temperature purified helium device, a programmable power supply, a PLC logic control unit, and a workstation computer;

[0009] The temperature sensor and pressure gauge on the low-temperature purified helium device are connected to the workstation computer through the data acquisition bus, the workstation computer is connected to the programmable power supply and the PLC logic control unit, and the programmable power supply and the PLC logic control unit are connected to the superconducting quench protection circuit sample in the low-temperature purified helium device through the relay group; a number of superconducting quench protection circuit samples are inserted into the low-temperature purified helium device, and the data collected by the sensors in the low-temperature purified helium device are transmitted to the workstation computer through the data acquisition bus, and the MCGS program set in the workstation computer is used to determine whether the test environment reaches the set conditions; the workstation computer transmits instructions to the PLC logic control unit through the RJ45 port, and transmits the setting program to the programmable power supply; the PLC logic control unit controls the relay group through the RS232 port; the programmable power supply loads the program signal on the workstation computer to the quench protection circuit sample through the relay group and the 37-core cable, and collects data to the data acquisition bus; and then returns it to the workstation computer.

[0010] The present invention also provides a low-temperature helium purification device, comprising an outer shell, an inner shell heat insulation screen, a liquid helium inner shell, a tray, a lower gas baffle, a liquid helium inlet pipe, a helium column, a conductive column, an upper gas baffle, a neck insulation tube, a neck tube, a liquid helium input joint, a safety valve, an upper cover, a helium column outlet and a helium outlet; the outer shell is wrapped around the liquid helium inner shell, the top of the liquid helium inner shell is provided with a neck tube extending from the outer shell, and the side wall of the neck tube extending from the outer shell is provided with a safety valve and a helium outlet; the inner wall of the neck tube is provided with a neck insulation tube, the middle part of the neck tube is provided with a helium column extending into the liquid helium inner shell, and the middle part of the helium column is provided with a conductive column; the top of the neck tube is provided with an upper cover, and the upper part of the helium column is provided with a helium column outlet;

[0011] A helium column located inside the liquid helium liner is provided with a plurality of tray groups at equal intervals from top to bottom, and each tray group includes a plurality of trays circumferentially distributed on the outer wall of the helium column at equal intervals; a quench protection circuit sample is provided on the tray, an upper gas baffle and a lower gas baffle are provided above and below the liquid helium liner respectively, a liquid helium inlet pipe is provided in the space formed between the liquid helium liner and the outer shell, one end of the liquid helium inlet pipe extends out of the top of the outer shell and is provided with a liquid helium input connector, and the other end of the liquid helium inlet pipe is connected to the bottom of the liquid helium liner;

[0012] There is a hole at the bottom of the helium column. After passing through the helium cooling superconducting magnet quench protection circuit, part of the gas is discharged from the helium column outlet, and the rest is discharged from the helium outlet after passing through the upper gas baffle and the neck insulation tube.

[0013] Furthermore, the outer wall of the neck tube is provided with annular inner liner heat insulation screens at equal intervals from top to bottom, and the inner liner heat insulation screens have a curvature.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0015] 1. The low-temperature purified helium device in this system can input and output helium at the same time. There will be no waste of cryogenic working fluid during the cooling and heating process, which improves the utilization rate and efficiency of precious helium resources.

[0016] 2. The system adopts superconducting closed-loop input variables and output control logic, which can quickly obtain the action sequence of the quench protection circuit and quickly obtain the protection effect.

[0017] 3. Through the system of the present invention and the low-temperature helium purification device, it is no longer necessary to detect the characteristics of individual superconducting protection coils one by one, thereby reducing the test cost and preparation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the performance testing system of the present invention;

[0019] Figure 2 It is a schematic diagram of the structure of a low-temperature helium purification device. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] Figure 1 The performance test system of the superconducting quench protection circuit in the liquid helium temperature zone designed by the present invention is provided, comprising a low-temperature purified helium device, a programmable power supply, a PLC logic control unit, and a workstation computer; a plurality of superconducting quench protection circuit samples are inserted into the low-temperature purified helium device. The low-temperature purified helium device is cooled by filling liquid in an external liquid helium pipeline, and the data collected by the sensor in the low-temperature purified helium device is transmitted to the data acquisition bus through a 4-core cable, and then transmitted to the workstation computer. The MCGS program in the workstation computer determines the comparison result between the test environment parameters and the set values, and transmits the instructions to the PLC logic control unit and the set program to the programmable power supply through the RJ45 port; the PLC logic control unit controls the relay group through the RS232 port, and the test power supply loads the program signal through the relay group, and loads it to the quench protection circuit sample through the 37-core cable, and collects it to the data acquisition bus through the output loop; and then returns it to the workstation computer.

[0022] When working, the 220V, 50HZ power frequency voltage is used to input 24V DC power supply through fuses and circuit breakers to power the entire performance test system. In the multi-channel test circuit, several input signals output by the relay group are input into the sample. The MCGS program logic determines whether the test conditions are met, and then automatically collects the output signal and outputs the final result.

[0023] Figure 2 1 is a schematic diagram of the structure of a low-temperature helium purification device, which includes an outer shell 1, an inner shell heat insulation screen 2, a liquid helium inner shell 3, a tray 4, a lower gas baffle 5, a liquid helium inlet pipe 6, a helium column 7, a conductive column 8, an upper gas baffle 9, a neck insulation tube 10, a neck tube 11, a liquid helium input connector 12, a safety valve 13, an upper cover 14, a helium column outlet 15 and a helium outlet 16; the outer shell 1 is wrapped around the liquid helium inner shell 3, the top of the liquid helium inner shell 3 is provided with a neck tube 11 extending from the outer shell 1, and the side wall of the neck tube 11 extending from the outer shell 1 is provided with a safety valve 13 and a helium outlet 16; the inner wall of the neck tube 11 is provided with a neck insulation tube 10, and the middle part of the neck tube 11 is provided with a helium column 7 extending into the liquid helium inner shell 3, and the helium column 7 A conductive column 8 is provided in the middle; an upper cover 14 is provided on the top of the neck tube 11, and a helium column outlet 15 is provided on the upper part of the helium column 7;

[0024] The helium column 7 located inside the liquid helium liner 3 is provided with a plurality of tray groups at equal intervals from top to bottom, and each tray group includes a plurality of trays 4 circumferentially distributed on the outer wall of the helium column 7 at equal intervals; a superconducting magnet quench protection circuit is provided on the tray 4, an upper gas baffle 9 and a lower gas baffle 5 are provided above and below the liquid helium liner 3, respectively, a liquid helium inlet pipe 6 is provided in the space formed between the liquid helium liner 3 and the outer shell 1, one end of the liquid helium inlet pipe 6 extends out of the top of the outer shell 1 and is installed with a liquid helium input connector 12, and the other end of the liquid helium inlet pipe 6 is connected to the bottom of the liquid helium liner 3;

[0025] A hole is provided at the bottom of the helium column 7. After passing through the helium cooling superconducting magnet quench protection circuit, part of the gas is discharged from the helium column outlet 15, and the rest is discharged from the helium outlet 16 after passing through the upper gas baffle 9 and the neck insulation tube 10.

[0026] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A performance test system for a superconducting quench protection circuit in a liquid helium temperature range, characterized in that: It includes a low-temperature helium purification device, a programmable power supply, a PLC logic control unit, and a workstation computer; The temperature sensor and pressure gauge on the low-temperature purified helium device are connected to the workstation computer through the data acquisition bus, the workstation computer is connected to the programmable power supply and the PLC logic control unit, and the programmable power supply and the PLC logic control unit are connected to the superconducting quench protection circuit sample in the low-temperature purified helium device through the relay group; a number of superconducting quench protection circuit samples are inserted into the low-temperature purified helium device, and the data collected by the sensors in the low-temperature purified helium device are transmitted to the workstation computer through the data acquisition bus, and the MCGS program set in the workstation computer is used to determine whether the test environment reaches the set conditions; the workstation computer transmits instructions to the PLC logic control unit through the RJ45 port, and transmits the setting program to the programmable power supply; the PLC logic control unit controls the relay group through the RS232 port; the programmable power supply loads the program signal on the workstation computer to the quench protection circuit sample through the relay group and the 37-core cable, and collects data to the data acquisition bus; Then return to the workstation computer.

2. A low temperature helium purification device, characterized in that: The invention comprises an outer shell (1), an inner shell heat insulation screen (2), a liquid helium inner shell (3), a tray (4), a lower gas baffle (5), a liquid helium inlet pipe (6), a helium column (7), a conductive column (8), an upper gas baffle (9), a neck insulation tube (10), a neck tube (11), a liquid helium input joint (12), a safety valve (13), an upper top cover (14), a helium column outlet (15) and a helium outlet (16); the outer shell (1) is wrapped around the liquid helium inner shell (3), and the top of the liquid helium inner shell (3) is provided with a A neck tube (11) extends out of the outer shell (1), and a safety valve (13) and a helium outlet (16) are provided on the side wall of the neck tube (11) extending out of the outer shell (1); a neck insulation tube (10) is provided on the inner wall of the neck tube (11); a helium column (7) extending into the interior of the liquid helium liner (3) is provided in the middle of the neck tube (11); a conductive column (8) is provided in the middle of the helium column (7); an upper cover (14) is provided on the top of the neck tube (11), and a helium column outlet (15) is provided on the upper part of the helium column (7); A helium column (7) located inside a liquid helium liner (3) is provided with a plurality of tray groups at equal intervals from top to bottom, each tray group comprising a plurality of trays (4) circumferentially and evenly distributed on the outer wall of the helium column (7); a quench protection circuit sample is provided on the tray (4); an upper gas baffle (9) and a lower gas baffle (5) are provided above and below the liquid helium liner (3), respectively; a liquid helium inlet pipe (6) is provided in the space formed between the liquid helium liner (3) and the outer shell (1); one end of the liquid helium inlet pipe (6) extends out of the top of the outer shell (1) and is provided with a liquid helium input connector (12); the other end of the liquid helium inlet pipe (6) is connected to the bottom of the liquid helium liner (3); A hole is provided at the bottom of the helium column (7), and part of the gas is discharged from the helium column outlet (15) after passing through the helium cooling superconducting magnet quench protection circuit, and the rest of the gas is discharged from the helium outlet (16) after passing through the upper gas baffle (9) and the neck insulation tube (10).

3. The device for low temperature purification of helium according to claim 2, characterized in that: The outer wall of the neck tube (11) is provided with annular inner liner heat insulation screens (2) at equal intervals from top to bottom, and the inner liner heat insulation screens (2) are curved.

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