Dynamic simulation test platform and method for ultra-high-speed evacuated tube magnetic levitation (maglev) transportation

A dynamic simulation test platform for ultra-high-speed evacuated tube magnetic levitation (maglev) transportation includes an evacuated tube having a transition section and a vacuum section, a vacuum maintaining system, a motor supporting platform, and a model train. One end of the evacuated tube is provided with a first isolation door, and the other end is closed. A second isolation door is provided inside the evacuated tube. The vacuum maintaining system is connected to the transition section and the vacuum section. The motor supporting platform is provided in the evacuated tube and extends outside the transition section. The motor supporting platform is provided with a stator winding and a permanent-magnet track. A mover and a cryogenic dewar are provided at a bottom of the model train. The cryogenic dewar is provided with a superconducting bulk. A test method using the test platform is further provided.

TECHNICAL FIELD

This application relates to high-speed operation test, and more particularly to a dynamic simulation test platform and method for ultra-high-speed evacuated tube magnetic levitation (maglev) transportation.

BACKGROUND

In recent years, some progress has been made to the high-temperature superconducting (HTS) pinning magnetic levitation technology in terms of the improvement of loading capacity and dynamic levitation stability, and the research and development of application prototypes. However, a test platform suitable for researching the basic scientific problems and common key technologies involving multiple disciplines (e.g., maglev transportation aerodynamics, levitation and guidance, traction and control, high-power rail electromagnetic propulsion, and tube-rail-train-airflow-thermal coupling) under the multi-state coupling condition is still absent in the prior art.

SUMMARY

In view of the deficiencies in the prior art, this application provides a dynamic simulation test platform and method for ultra-high-speed evacuated tube magnetic levitation (maglev) transportation.

Technical solutions of this application are described as follows.

This application provides a dynamic simulation test platform for evacuated tube magnetic levitation (maglev) transportation, comprising:an evacuated tube;a vacuum maintaining system;a motor supporting platform; anda test train;wherein a first end of the evacuated tube is provided with a first isolation door, and a second end of the evacuated tube is closed; a second isolation door is provided inside the evacuated tube; and the second isolation door is configured to divide the evacuated tube into a transition section and a vacuum section;the vacuum maintaining system is connected to the transition section and the vacuum section;the motor supporting platform is provided in the evacuated tube, and extends out of the transition section; and the motor supporting platform is provided with a stator and a permanent-magnet track;a mover and a cryogenic dewar are provided at a bottom of the test train; a superconducting bulk is provided inside the cryogenic dewar; the stator is configured to be energized to generate a driving force with the mover to drive the test train forward; and the superconducting bulk is configured to cooperate with the permanent-magnet track to generate a levitation force; andthe dynamic simulation test platform is operated through steps of:performing a manual inspection on hardware equipment; and vacuumizing the evacuated tube to reach a first target pressure;starting an energy storage device of a traction-braking system to perform energy storage until the energy storage is completed;feeding liquid nitrogen to the cryogenic dewar; connecting the test train to the mover after completing the feeding of liquid nitrogen; transferring the test train and the mover to the transition section; and closing the first isolation door;opening a first connecting valve between the transition section and the vacuum maintaining system; and vacuumizing the transition section to reach a second target pressure;opening the second isolation door; opening a second connecting valve between the vacuum section and the vacuum maintaining system; and adjusting a pressure in the evacuated tube to the first target pressure and keeping the pressure in the evacuated tube at the first target pressure;starting a test and communication system to perform time synchronization and acquisition of test data;starting the traction-braking system for controlling the test train to accelerate, travel at a constant speed, and decelerate;saving the test data; turning off the traction-braking system and the test and communication system in turn;controlling a multifunctional testing vehicle to return the test train to the transition section;closing the second isolation door; restoring a pressure of the transition section to atmospheric pressure; opening the first isolation door; and moving the test train out of the transition section to a preparation section;if there is no other test to be conducted in a preset period of time, closing the first connecting valve and the second connecting valve; and closing the vacuum maintaining system to restore the pressure in the evacuated tube; andclosing the dynamic simulation test platform when a temperature in the evacuated tube reaches an ambient temperature.

In an embodiment, the motor supporting platform is provided with two motor brackets; the motor supporting platform is fixedly connected to the evacuated tube; one of the two motor brackets is disposed on a first side of the motor supporting platform, and the other of the two motor brackets is disposed on a second side of the motor supporting platform; a first gap is provided between the two motor brackets; the number of the stator is two; one of two stators is provided on a sidewall of one of the two motor brackets, and the other of the two stators is provided on a sidewall of the other of the two motor brackets; the two stators are located in the first gap; the mover is located between the two stators; and a second gap is provided between the mover and each of the two stators.

In an embodiment, each of the two stators comprises a stator core and a stator winding; the stator core is fixedly connected to a corresponding one of the two motor brackets; the stator winding is fixedly connected to the stator core; and the stator winding is located in the first gap.

In an embodiment, the dynamic model test platform further includes a position detecting device; wherein the position detecting device is provided on one of the two motor brackets and located in the first gap.

In an embodiment, the mover is made of permanent magnets.

In an embodiment, the transition section is made of a transparent material; and the vacuum section is made of a metal material.

In an embodiment, the dynamic model test platform further includes three bases; wherein the three bases are fixedly connected to the ground; an end of each of the three bases away from the ground is provided with a tube supporting seat; two of three tube supporting seats are connected to the first isolation door and the second isolation door, respectively; and a remaining one of the three tube supporting seats is fixedly connected to a closed end of the evacuated tube.

In an embodiment, the permanent-magnet track is arranged in a Halbach array.

In an embodiment, the step of “performing a manual inspection on hardware equipment; and vacuumizing the evacuated tube to reach a first target pressure” is performed through steps of:at 48 h before test, performing the manual inspection on the hardware equipment;at 24 h before the test, closing the first isolation door; starting the vacuum maintaining system to vacuumize the evacuated tube until the pressure in the evacuated tube reaches the first target pressure; and keeping the evacuated tube at the first target pressure; andat 2 h before the test, based on a monitoring system, setting test parameters; checking equipment data; and setting an interlocked operation according to test requirements.

Compared to the prior art, this application has the following beneficial effects.(1) In this application, the superconducting pinning effect is generated by the superconducting bulk and the permanent-magnet track, thereby realizing the passive stable levitation and guiding function of the test train. Compared with the traditional “8”-shaped superconducting electrodynamic suspension, the complexity of the levitation and guiding of the test train is greatly reduced, and the stability and reliability of the system operation are improved.(2) The vacuum maintenance system vacuumizes the evacuated tube. The first isolation door and the second isolation door change gas pressure in the evacuated tube, making the test train run under different gas pressures, effectively reducing the air resistance, improving the aerodynamic noise, and realizing the test under different gas pressures. This application completes the comprehensive experimental research and validation of rail transportation system in different operating environments under different gas pressures and at different operating speeds, and realizes the research on the basic scientific problems and common key technologies based on multi-disciplinary intersection of wheel-rail (magnetic rail) dynamics, aerodynamics, levitation and guidance, traction and control, high-power rail electromagnetic propulsion, and pipeline-rail-train-airflow-thermal coupling under the condition of multi-state coupling.

Other features and advantages of the present disclosure will be described below. Some features and advantages will become apparent from the specification or be understood by implementing the embodiments. The objects and other advantages of the present disclosure may be obtained by the structure indicated in the specification, the appended claims, and the accompanying drawings.

DETAILED DESCRIPTION OF EMBODIMENTS

The technical solutions of the disclosure will be described in detail below with reference to the drawings in the embodiments to make the technical solutions, objects and advantages of the disclosure clearer. Obviously, described below are merely some embodiments of the disclosure, which are not intended to limit the disclosure. It should be noted that the components of the embodiments shown in the drawings herein may be arranged and designed in different forms. Accordingly, the following detailed description is merely illustrative, and is not intended to limit the scope of the disclosure. For those skilled in the art, other embodiments obtained based on these embodiments without paying creative efforts should fall within the scope of the disclosure defined by the appended claims.

It should be noted that similar reference signs and letters indicate similar items in the drawings. Thus, once an element has been defined in one drawing, there is no need to further define and explain this element in subsequent drawings. In addition, the terms “first” and “second” are merely descriptive, and cannot be understood as indicating or implying relative importance.

As shown inFIG.1, a dynamic model test platform for ultra-high-speed evacuated tube magnetic levitation (maglev) transportation includes an evacuated tube6, a vacuum maintaining system18, a motor supporting platform8, and a test train1. The first end of the evacuated tube6is provided with a first isolation door13, and the second end of the evacuated tube6is closed. Specifically, the tail end of the evacuated tube6is flanged and sealed with the pipe section by a vessel header. A second isolation door19is provided inside the evacuated tube6. The second isolation door19is configured to divide the evacuated tube6into a transition section14and a vacuum section20. The vacuum maintaining system18is connected to the transition section14and the vacuum section20, respectively. The motor supporting platform8is provided in the evacuated tube6and extends out of the transition section14. The motor supporting platform8is provided with two stators and a permanent-magnet track9. Specifically, the permanent-magnet track9is arranged in a Halbach array. The bottom of the test train1is provided with a mover2and a cryogenic dewar4. In an embodiment, the bottom of the test train1is provided with a connecting structure. The mover2and the cryogenic dewar4are provided on the connecting structure. In an embodiment, the connecting structure may be a bogie in the prior art. A superconducting bulk21is provided inside the cryogenic dewar4. The stator is configured to be energized to generate a driving force with the mover2to drive the test train1forward. The superconducting bulk21is configured to cooperate with the permanent-magnet track9to generate a repulsive force. It should be noted that the cryogenic dewar4is used to hold liquid nitrogen for cooling the superconducting bulk21. The superconducting bulk21enters a superconducting state in a low temperature environment, and produces a superconducting pinning effect with the permanent-magnet track9, realizing the passive stable levitation and guiding function of the test train1. Compared with the traditional “8”-shaped superconducting electrodynamic suspension, the high-temperature superconducting bulk21used in this disclosure cooperates with the permanent-magnet track9to provide levitation and guidance, which can greatly reduce the complexity of the levitation and guidance of the test train1, and improve the stability and reliability of the system operation. In this disclosure, the vacuum maintaining system18vacuumizes the evacuated tube6. The first isolation door13and the second isolation door19change gas pressure in the evacuated tube6, allowing the test train1to run under different gas pressures, effectively reducing the air resistance, improving the aerodynamic noise, and realizing the test under different gas pressures. This disclosure completes the comprehensive experimental research and validation of rail transportation system in different operating environments under different gas pressures and at different operating speeds, and realizes the research on the basic scientific problems and common key technologies based on multi-disciplinary intersection of wheel-rail (magnetic rail) dynamics, aerodynamics, levitation and guidance, traction and control, high-power rail electromagnetic propulsion, and pipeline-rail-train-airflow-thermal coupling under the condition of multi-state coupling.

As shown inFIG.2, the motor supporting platform8is provided with two motor brackets5. The motor supporting platform8is fixedly connected to the evacuated tube6. The two motor brackets5are respectively disposed on both sides of the motor supporting platform8. A first gap22is provided between the two motor brackets5. The number of the stator is two. The two stators are disposed on the sidewall of the motor bracket5, respectively. The two stators are disposed in the first gap22. The mover2is located between the two stators. A second gap23is provided between the mover2and each of the two stators. In this way, a bilaterally linear drive motor provides the driving force for the test train1. Moreover, the bilateral drive can strengthen the driving force of the mover2, so that the mover2can reach a high speed in a short distance.

In this disclosure, the length of the evacuated tube6is not larger than 1.62 km, and the diameter of the evacuated tube6is not less than 3.0 m. The length of the section of the motor supporting platform8extending outside the transition section14is 17 m and recorded as the preparation section17. The length of the transition section14is 20 m, and the length of the vacuum section20is 1600 m. The vacuum section20includes a plurality of pipe sections welded together. In an embodiment, the length of each of the pipe sections is 20 m, and the number of the pipe sections is 81.

A stator supporting frame12is provided in the joint between the stator and the motor bracket5. The stator supporting frame12is made of aluminum. The stator includes a stator core10and a stator winding11. The stator core10is fixedly connected to a corresponding one of the two motor brackets5, the stator winding11is fixedly connected to the stator core10, and the stator winding11is disposed in the first gap22. The mover2is made of permanent magnets. In the present disclosure, according to the position of the test train1and predetermined rules, the stator winding11is intermittently energized to generate a magnetic field and repel the permanent magnets of the mover2, thereby driving the test train1. Under the action of the bilateral magnetic field, the high-temperature superconducting magnetic levitation test train1with a mass of 200 kg reaches a maximum speed of 1500 km/h.

Further, in order to obtain the position of the test train1at each moment, the dynamic model test platform further includes a position detecting device7. The position detecting device7is provided on one of the two motor brackets5. The position detecting device7is located in the first gap22. In an embodiment, the position detecting device7detects the position of the mover2, and then the position is converted to the position in which the test train is located, thereby detecting the position of the test train1. In an embodiment, the position detecting device7may be a laser rangefinder. The mover2is provided with projections arranged in a predetermined rule to exclude the influence caused by high speed. For example, a first group of projections are arranged in different spacings, a second group of projections are arranged in same spacings, and a third group of projections are arranged in different spacings. The spacings in the first group of projections are all smaller than the spacings used in the third group of projections. As a result, when detecting the distance signals, the distance changes having different cycles caused by the first projection group first appear; the distance changes caused by the second projection group have a relatively stable cycle; and then the distance changes with different cycles caused by the third projection group appear. The cycles of the distance changes caused by the first projection group are smaller than the cycles of the distance changes caused by the third projection group. Equipment errors are sequentially eliminated during the high-speed running, and the moving state of the test train1in the whole test process is indirectly determined.

In order to strengthen the structure of the evacuated tube6and observe the state of the test train1and other equipment in the preparation stage in real time, the transition section14of the evacuated tube6is made of a transparent material, and the vacuum section20of the evacuated tube6is made of a metal material. Specifically, in an embodiment, the metal material is steel, and the transparent material is transparent tempered borosilicate glass. The thickness of the tempered borosilicate glass is 20 mm. The tempered borosilicate glass is provided with T-shaped stiffening ribs at every 2 m of the tempered borosilicate glass. A sealing ring is provided between the tempered borosilicate glass and the stiffening rib for sealing. The transition section14can effectively maintain the long-term low-pressure state of the pipe, so that the test train1transitions between atmospheric pressure and low-pressure, simulating the function of the transition cabin of the station during use.

Meanwhile, in order to support the vacuum maintaining system18, the dynamic model test platform further includes three bases16. Each of the three bases16is fixedly connected to the ground. An end of each of the three bases16away from the ground is provided with a tube supporting seat15. Two of the three tube supporting seats15are connected to the first isolation door13and the second isolation door19, respectively. A remaining one of the three tube supporting seats15is fixedly connected to a closed end of the evacuated tube6.

Referring toFIG.3, in order to make the pressure within the evacuated tube6continuously adjust and keep in the range of 0.005˜1.0 atm, the vacuum maintaining system18is the vacuum pump three-stage dry system. The pressure of the tube is 0.005˜1.0 atm. The time needed for adjusting the pressure from 1.0 atm to 0.005 atm is ≤24 h. The control system is configured with independent electric control cabinet, and PLC+HMI control and one-key start function, which can optimize pumping speed. After reaching the target pressure, the pumping speed is reduced or the pump is gradually stopped to maintain the vacuum state, thereby achieving the effect of energy saving. The pressure in the tube is continuously adjustable within the range of 0.0051.0 atm. Each vacuum pump needs to be equipped with a frequency converter, allowing the vacuum pumps to start together at atmospheric pressure. Each vacuum pump should be equipped with a solenoid-pneumatic switching valve at the inlet or exhaust port of the vacuum pump, thereby quickly opening and closing the vacuum pump. The dry system should be equipped with a pressure control assembly to regulate the frequency of the vacuum pump or control the solenoid-pneumatic switching valve or adjust the pressure of the exhaust side. The dry system is sealed by metal, which can withstand a large amount of dust and ensure reliable sealing in the environment containing impurities. The Programmable Logic Controller (PLC) of the electronic control system should adopt world first-class brand equipment. The electronic control communication method of the vacuum maintaining system adopts Profinet and is connected to the Profinet port of the control system. The unit PLC is connected to the frequency converter of the vacuum pump to accept the command of the upper computer, control the vacuum pump and regulate the pressure, and collect and transmit the temperature/current/frequency/failure/alarm signals of the vacuum pump to the upper computer at the same time. The unit PLC collects the vacuum gauge signal and control the feedback signals of valve switch and valve position. The unit controls remotely and locally a human-machine interface, which displays the operating status of the vacuum pump and valve, vacuum gauge pressure value, and operating frequency and operating time of each pump.

The dynamic simulation test platform is operated through the following steps.

The vacuum section20is pumped, and the gas pressure in the vacuum section20is maintained at a preset gas pressure for the test.

The test train1is subjected to debugging in the preparation section17.

After finishing the debugging, the first isolation door13is opened, and the test train1is driven under the cooperation of the stator and the mover2to enter the transition section14.

The first isolation door13is closed, and the vacuum maintaining system18is used to perform air extraction on the transition section14and maintain the gas pressure in the transition section14at the first gas pressure. In an embodiment, the first gas pressure is higher than the preset gas pressure for test.

The second isolation door19is opened, and the test train1is driven into the vacuum section20through the stator in cooperation with the mover2. The vacuum section20is performed with the air extraction, and the gas pressure in the vacuum section20is maintained at the preset gas pressure for test.

The test data is collected in accordance with the preset running speed.

In this embodiment, by testing the test train1driving into the vacuum section20in the manner described above, the structural strength of the transition section14can be carefully considered. Through the intermediate transition of the first gas pressure value, the gas pressure to which the transition section14is subjected can be reduced. Moreover, the state observation of the test train1and other equipment is achieved through the transition section14, and the time required for the test train1to travel from the outside into the vacuum section20is shortened, and the time required to maintain the vacuum section20at the designed pressure value is reduced.

The dynamic simulation test platform is operated through the following steps.(S1) A manual inspection is performed on hardware equipment. The evacuated tube6is vacuumized to reach a first target pressure.(S11) At 48 h before the test, the manual inspection is performed on the hardware equipment.

In this embodiment, the manual inspection of the hardware equipment includes: 1. checking the condition of the system equipment and eliminating abnormalities, such as ensuring that the first isolation door13and pointer pressure gauge are normal; whether the cables and wires are flooded or not; and whether there is a disaster such as obvious settlement of the foundation; 2. confirming that the second isolation door19is open; the first isolation door13is closed; the pipes and valves of the vacuum maintaining system18are in normal condition; the test train1and on-board test equipment of the test train1is intact; the line switch of the driving-braking system (including power electronic switch) is normal; the lubrication and cooling status of the energy storage system is normal; the test and communication system is energized and reset; the environmental control system and the integrated monitoring system is activated; the multi-functional testing vehicle runs to the parking position at the end; and the test conditions in the pipes have met the requirements; and cleaning up the test area.

It should be noted that the line switches for the driving-braking system refers to the electrical switches such as the mover2and the stator windings, as well as the switches for the complete system of the cryogenic dewar. The energy storage system, the test and communication system, the environmental control system and the integrated monitoring system are the relevant safeguard systems of the test train1, respectively.(S12) At 24 hours before the test, the first isolation door13is closed. The vacuum maintaining system18is activated to vacuumize the evacuated tube6until the pressure in the evacuated tube6reaches the second target pressure, and the pressure in the evacuated tube6is maintained at the second target pressure to ensure that the pressure fluctuation is less than 5%.(S13) At 2 hours before the test, based on the integrated monitoring system, the relevant test parameters are set, the relevant equipment data is checked, and an interlocked operation is set according to the test requirements.(S2) The energy storage device of the traction-braking system is started to store energy until the energy storage is completed.(S3) The cryogenic dewar4is filled with liquid nitrogen. The test train1is connected to the mover after finishing filling liquid nitrogen. The test train and the mover are transferred into the transition section14. The first isolation door13is closed.(S5) A first connecting valve24between the transition section14and the vacuum maintaining system18is opened. The transition section14is vacuumized to reach the second target pressure.(S6) The second isolation door19is opened. A second connecting valve25between the vacuum section20and the vacuum maintaining system18is opened. A pressure in the evacuated tube6is adjusted to the first target pressure and the pressure in the evacuated tube is kept at the first target pressure by the vacuum maintaining system.(S7) The test and communication system is started to perform time synchronization.(S8) The test and communication system is started to perform acquisition of the test data.(S9) The traction-braking system is started for controlling the test train1to accelerate, travel at a constant speed, and decelerate.(S10) The test data is saved. The traction-braking system and the test and communication system are turned off in turn.(S11) A multifunctional testing vehicle is controlled to return the test train1to the transition section14.(S12) The second isolation door19is closed. The transition section14is repressurized to atmospheric pressure. Then, the first isolation door13is opened. The test train1moves from the transition section14to the preparation section17.(S13) If there is no other test to be conducted in a preset period of time, the first connecting valve24and the second connecting valve25are closed, and the vacuum maintaining system18is closed to restore the pressure in the evacuated tube6.(S14) When the temperature inside the evacuated tube6reaches the ambient temperature, the dynamic simulation test platform is closed.

Described above are merely preferred embodiments of the disclosure, which are not intended to limit the disclosure. It should be understood that any modifications and replacements made by those skilled in the art without departing from the spirit of the disclosure should fall within the scope of the disclosure defined by the appended claims.