Magnetic levitation train and permanent magnet suspension system and control method

Abstract

The application discloses a maglev train, a permanent magnetic suspension system and a control method, and relates to the field of maglev trains.The permanent magnetic suspension system comprises a frame base, a linear driving mechanism, a vehicle-mounted permanent magnetic module, a first displacement sensor, a second displacement sensor and a control module; the linear driving mechanism, the first displacement sensor and the second displacement sensor are electrically connected with the control module; the frame base is arranged on a bogie of the maglev train, the linear driving mechanism is arranged on the frame base, and the vehicle-mounted permanent magnetic module is arranged on the linear driving mechanism; the control module controls the linear driving mechanism to act according to the transverse displacement of the vehicle-mounted permanent magnetic module relative to a permanent magnetic track or the transverse displacement of the vehicle-mounted permanent magnetic module relative to the permanent magnetic track and the transverse displacement of the bogie relative to the center of the track, so as to eliminate the transverse force suffered by the vehicle-mounted permanent magnetic module or make the bogie return to the center of the track.The application can realize zero-power stable suspension.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet levitation technology, and particularly relates to a maglev train, a permanent magnet levitation system, and a control method. Background Technology

[0002] Permanent magnet levitation is a type of magnetic levitation system characterized by strong levitation capability, low energy consumption, no electromagnetic radiation, and the ability to achieve zero-power levitation. For example... Figure 1 As shown, the permanent magnet track installed on the track beam or roadbed and the on-board permanent magnet module installed on the vehicle constitute the most basic permanent magnet levitation system. The magnetic poles of the permanent magnet track and the on-board permanent magnet module are opposite each other, which can generate a strong repulsive force without consuming electricity. At the same time, in order to improve the repulsive force, the on-board permanent magnet module and the permanent magnet track usually adopt a Halbach array that can concentrate magnetic energy on one side. Figure 1 The image shows the permanent magnet module and permanent magnet track of the Halbach array.

[0003] Despite the numerous advantages of permanent magnet levitation, it can be deduced from Enshao's theorem that a permanent magnet levitation system cannot achieve stable levitation solely through the static magnetic force of the permanent magnet unless control or constraint is applied. In practice, it has been found that while a permanent magnet levitation system can generate a large vertical force to achieve levitation, a slight deviation from the center of symmetry of the track will generate a lateral force, and this lateral force is in the same direction as the deviation; the greater the deviation, the greater the lateral force. Figure 2 As shown. This means that the permanent magnet levitation system has negative stiffness in the lateral direction, cannot maintain stability in the lateral direction, is an unstable system, is easily affected by external disturbances, and is difficult to achieve stable levitation.

[0004] In summary, the problem with permanent magnet levitation systems lies in lateral instability, making complete stable levitation impossible. Therefore, existing permanent magnet levitation systems address this lateral stability issue by adding mechanical or electromagnetic guiding mechanisms. However, mechanical guiding mechanisms introduce frictional resistance and noise due to contact with the track; while electromagnetic guiding mechanisms require continuous energization of the electromagnets through the introduction of electromagnetic coils, consuming electrical energy and generating electromagnetic radiation. Both of these solutions diminish the advantages of permanent magnet levitation. Summary of the Invention

[0005] The purpose of this invention is to provide a maglev train, a permanent magnet levitation system, and a control method to solve the problem that existing pure permanent magnet levitation systems cannot achieve stable levitation solely based on the magnetic force between permanent magnets.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution: a permanent magnet levitation system, the system comprising:

[0007] Framework basics;

[0008] A linear drive mechanism based on the aforementioned frame;

[0009] An on-board permanent magnet module is mounted on the linear drive mechanism, and the magnetic poles of the on-board permanent magnet module are opposite to those of the permanent magnet track;

[0010] A first displacement sensor is used to collect the lateral displacement between the vehicle-mounted permanent magnet module and the permanent magnet track.

[0011] A second displacement sensor is used to collect the lateral displacement of the bogie relative to the center of the track.

[0012] A control module is connected to the linear drive mechanism, the first displacement sensor, and the second displacement sensor respectively. The control module is used to control the linear drive mechanism to operate according to the lateral displacement collected by the first displacement sensor or the lateral displacement collected by the first displacement sensor and the second displacement sensor, so as to eliminate the lateral force on the on-board permanent magnet module or return the bogie to the center of the track.

[0013] Furthermore, the vehicle-mounted permanent magnet module employs a Halbach array.

[0014] Furthermore, the frame base is an inverted U-shaped structure, and a dust cover is provided at the opening of the inverted U-shaped structure. The linear drive mechanism, the vehicle-mounted permanent magnet module, and the first displacement sensor are located in the cavity formed by the inverted U-shaped structure and the dust cover.

[0015] Furthermore, the linear drive mechanism includes a linear guide rail and a linear drive device; the linear guide rail includes a guide rod and a slider, the guide rod is fixed on the frame foundation, the slider is slidably disposed on the guide rod, the vehicle-mounted permanent magnet module is disposed on the slider, and the linear drive device is connected to the vehicle-mounted permanent magnet module.

[0016] Furthermore, the linear drive device includes a drive motor and a lead screw and nut mechanism. The output end of the drive motor is connected to the lead screw of the lead screw and nut mechanism, and the lead screw and nut mechanism is connected to the vehicle-mounted permanent magnet module.

[0017] When the drive motor drives the lead screw to rotate, the ball nut of the lead screw nut mechanism drives the on-board permanent magnet module to move laterally along the guide rod.

[0018] Furthermore, the linear drive device is a permanent magnet synchronous linear motor, the stator of the permanent magnet synchronous linear motor is fixed on the frame base, and the vehicle-mounted permanent magnet module is connected to the mover of the permanent magnet synchronous linear motor.

[0019] Furthermore, the linear drive device is a synchronous belt drive mechanism, which includes a driving pulley, a driven pulley, a synchronous belt wound around the driving pulley and the driven pulley, and a drive motor; the driving pulley and the driven pulley are fixed on the frame foundation, the output end of the drive motor is connected to the driving pulley, and the synchronous belt is connected to the vehicle-mounted permanent magnet module through a pressure plate.

[0020] Based on the same concept, the present invention provides a control method for the permanent magnet levitation system described above, the control method comprising the following steps:

[0021] When the permanent magnet levitation system is in the levitation mode, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor is zero.

[0022] When the permanent magnet levitation system is in the levitation mode, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor increases until the repulsive force between the on-board permanent magnet module and the permanent magnet track is reduced to a level that is insufficient to support the levitation of the train.

[0023] When the permanent magnet levitation system is in levitation mode and there are no guide devices on both sides of the bogie, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor and the second displacement sensor, and the bogie is returned to the center of the track by the lateral force on the on-board permanent magnet module.

[0024] When the permanent magnet levitation system is in levitation mode and guide devices are installed on both sides of the bogie, the linear drive mechanism is controlled to operate based on the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor is zero.

[0025] Furthermore, when the permanent magnet levitation system is in levitation mode and no guide devices are installed on both sides of the bogie, a two-stage PID controller is used to control the linear drive mechanism, specifically as follows:

[0026] The lateral displacement collected by the second displacement sensor is input to the first-stage PID controller to obtain the first control quantity;

[0027] The difference between the first control quantity and the lateral displacement collected by the first displacement sensor is input to the second-stage PID controller to obtain the second control quantity;

[0028] The linear drive mechanism is controlled according to the second control quantity. The lateral force on the onboard permanent magnet module is used to return the bogie to the center of the track. That is, by actively controlling the movement of the onboard permanent magnet module, the lateral force on the onboard permanent magnet module is transformed into a restoring force that returns the bogie to the center of the track.

[0029] Based on the same concept, the present invention also provides a maglev train, wherein a permanent magnet levitation system as described above is provided at the bottom of the bogie of the maglev train, and no guide device is provided on both sides of the bogie.

[0030] Alternatively, a permanent magnet levitation system as described above may be provided at the bottom of the bogie of the maglev train, and guide devices may be provided on both sides of the bogie.

[0031] Furthermore, the guiding device is a permanent magnet levitation system, an electromagnet, or a guide wheel as described above;

[0032] When the guiding device is an electromagnet, a ferromagnetic track plate is set on the track beam and the ferromagnetic track plate corresponds to the electromagnet; when the guiding device is a guide wheel, the guide wheel contacts the track beam.

[0033] Beneficial effects

[0034] Compared with the prior art, the advantages of the present invention are as follows:

[0035] In the permanent magnet levitation system of this invention, the lateral force generated by the permanent magnet module on the vehicle under the action of the linear drive mechanism is transmitted to the vehicle body through the linear drive mechanism, the frame foundation, and the bogie. Since the mass of the vehicle body is much greater than the mass of the vehicle permanent magnet module, the vehicle permanent magnet module can resist the huge lateral force and move towards the center of the track. The lateral force will be dissolved during the transmission process of the two-stage suspension mechanism, eliminating the lateral instability caused by the negative stiffness lateral force, so that the permanent magnet levitation system only provides positive stiffness vertical force within a certain range.

[0036] Since the levitation force is still generated by the on-board permanent magnet module and the permanent magnet track, the system of the present invention retains the zero-power levitation characteristic of the existing permanent magnet levitation system. It only consumes a certain amount of energy to resist the deflection when the on-board permanent magnet module is moved. Compared with the electromagnetically guided permanent magnet levitation system, the present invention does not need to be continuously powered, thus reducing power consumption. Compared with the mechanically guided permanent magnet levitation system, the present invention will not come into contact with the track and generate frictional resistance and noise. Attached Figure Description

[0037] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram showing the combination and relative positions of the vehicle-mounted permanent magnet module and the permanent magnet track in the background technology of this invention;

[0039] Figure 2The background of this invention is the influence of the lateral offset or lateral displacement of the vehicle-mounted permanent magnet module on the lateral force;

[0040] Figure 3 This is a schematic diagram of the permanent magnet levitation system in an embodiment of the present invention;

[0041] Figure 4 This is a control flowchart of the permanent magnet levitation system in an embodiment of the present invention;

[0042] Figure 5 This is an active control permanent magnet levitation vehicle-track system without a guide device in this embodiment of the invention;

[0043] Figure 6 This is an active control permanent magnet levitation vehicle-track system guided by permanent magnets in this embodiment of the invention;

[0044] Figure 7 This is an electromagnetically guided active control permanent magnet levitation vehicle-track system in this embodiment of the invention;

[0045] Figure 8 This is an active control permanent magnet levitation vehicle-track system guided by mechanical (guide wheels) in this embodiment of the invention.

[0046] Explanation of reference numerals in the attached drawings: 1-Bogie, 101-Transverse suspension mechanism, 102-Vertical suspension mechanism, 2-Permanent magnet levitation system, 201-Frame foundation, 202-On-board permanent magnet module, 203-First displacement sensor, 204-Dust cover, 205-Linear drive mechanism, 2051-Drive motor, 2052-Lead screw, 2053-Ball nut, 2054-Slider, 2055-Guide rod, 3-Permanent magnet track, 4-Car body, 5-Air spring, 6-Rail beam, 7-Electromagnet, 8-Ferromagnetic track plate, 9-Guide wheel. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The technical solutions of this application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0049] Example 1

[0050] like Figure 3As shown, an embodiment of the present invention provides a permanent magnet levitation system 2 for maglev trains, comprising a frame foundation 201, a linear drive mechanism 205, an onboard permanent magnet module 202, a first displacement sensor 203, a second displacement sensor, and a control module; the linear drive mechanism 205, the first displacement sensor 203, and the second displacement sensor are electrically connected to the control module. The frame foundation 201 is mounted on the bogie 1 of the maglev train, the linear drive mechanism 205 is mounted on the frame foundation 201, and the onboard permanent magnet module 202 is mounted on the linear drive mechanism 205; when the linear drive mechanism 205 performs linear motion, it drives the onboard permanent magnet module 202 to move laterally, thereby changing the lateral displacement or lateral offset of the onboard permanent magnet module 202 relative to the permanent magnet track 3. Figure 3 As shown, A represents vertical, B represents longitudinal, and C represents transverse. Longitudinal refers to the direction of train movement, vertical refers to the direction of the plumb line, and transverse refers to the direction perpendicular to the longitudinal direction on the horizontal plane.

[0051] In this embodiment, the frame foundation 201 has an inverted U-shaped structure and is made of a non-magnetic metal material (such as stainless steel). The frame foundation 201 provides the mounting base for the various components of the permanent magnet levitation system 2 and is connected to the bogie 1 of the train through the frame foundation 201.

[0052] A dust cover 204 can also be installed at the opening of the inverted U-shaped structure. The linear drive mechanism 205, the vehicle-mounted permanent magnet module 202 and the first displacement sensor 203 are located in the cavity formed by the inverted U-shaped structure and the dust cover 204, which prevents water vapor, dust, oil and other substances from entering the system.

[0053] The vehicle-mounted permanent magnet module 202 is assembled from permanent magnet blocks in a specific arrangement. The simplest arrangement is for all permanent magnet blocks to face the same direction; preferably, they are arranged in a Halbach array to improve levitation. The vehicle-mounted permanent magnet module 202 contains at least one magnetic pole along its transverse direction, and the magnetic field distribution is uniform along its longitudinal direction. The vehicle-mounted permanent magnet module 202 and the permanent magnet track 3 are repelled by their similar magnetic poles, resulting in a repulsive force; the vertical component of this repulsive force is the levitation force. The vehicle-mounted permanent magnet module 202 is mounted on a linear drive mechanism 205, which allows it to move laterally. Similar to the vehicle-mounted permanent magnet module 202, the permanent magnet track 3 is laid along the entire length of the track.

[0054] The first displacement sensor 203 is fixedly mounted on the bottom of the vehicle-mounted permanent magnet module 202. When the gap between the vehicle-mounted permanent magnet module 202 and the permanent magnet track 3 is limited, the first displacement sensor 203 can also be fixedly mounted on the end of the vehicle-mounted permanent magnet module 202. The first displacement sensor 203 is used to collect the lateral displacement between the vehicle-mounted permanent magnet module 202 and the permanent magnet track 3. Based on the lateral displacement collected by the first displacement sensor 203, it can be determined whether the vehicle-mounted permanent magnet module 202 has undergone lateral displacement and the amount of lateral displacement. At the same time, the first displacement sensor 203 can also collect the gap between the vehicle-mounted permanent magnet module 202 and the permanent magnet track 3. In this embodiment, the first displacement sensor 203 is a Hall displacement sensor.

[0055] The second displacement sensor is mounted on the bogie 1 frame and is used to collect the lateral displacement of the bogie 1 relative to the track center. Based on the lateral displacement collected by the second displacement sensor, it can be determined whether the bogie 1 has experienced lateral deviation and the amount of lateral deviation. The track center refers to the center of the entire train's running track, not the center of the permanent magnet track 3.

[0056] Under the control of the control module, the linear drive mechanism 205 converts electricity into linear motion, driving the on-board permanent magnet module 202 to move laterally relative to the permanent magnet track 3 (or frame foundation 201). The linear drive mechanism 205 includes a linear guide rail and a linear drive device; the linear guide rail includes a guide rod 2055 and a slider 2054. The guide rod 2055 is fixed to the frame foundation 201, and the slider 2054 is slidably mounted on the guide rod 2055. The on-board permanent magnet module 202 is mounted on the slider 2054, and the linear drive device is connected to the on-board permanent magnet module 202. The linear drive device can be implemented in various ways, such as a screw-nut mechanism driven by a rotary motor, a synchronous belt drive mechanism, or a linear motor direct drive.

[0057] When the linear drive transposer uses a rotary motor-driven screw and nut mechanism, the linear drive device includes a drive motor 2051 and a screw and nut mechanism. The screw and nut mechanism (including a ball nut 2053 and a lead screw 2052) is connected to the on-board permanent magnet module 202, and the output end of the drive motor 2051 is connected to the lead screw 2052 of the screw and nut mechanism. The drive motor 2051 can be a permanent magnet synchronous motor, a stepper motor, or a servo motor. When the drive motor 2051 drives the lead screw 2052 to rotate, the ball nut 2053 of the screw and nut mechanism drives the on-board permanent magnet module 202 to move laterally along the guide rod 2055.

[0058] When the linear drive device is a synchronous belt drive mechanism, the synchronous belt drive mechanism includes a driving pulley, a driven pulley, a synchronous belt wound around the driving pulley and the driven pulley, and a drive motor; the driving pulley and the driven pulley are fixed on the frame base 201, the output end of the drive motor is connected to the driving pulley, and the synchronous belt is connected to the vehicle-mounted permanent magnet module 202 through a pressure plate. The drive motor can be a permanent magnet synchronous motor, a stepper motor, or a servo motor. When the drive motor drives the driving pulley to rotate, the driving pulley drives the synchronous belt to move, pulling the vehicle-mounted permanent magnet module 202 connected to the synchronous belt to move laterally along the guide rod 2055.

[0059] When the linear drive device is a permanent magnet synchronous linear motor, the stator of the permanent magnet synchronous linear motor is fixed on the frame foundation 201, and the vehicle-mounted permanent magnet module 202 is connected to the mover of the permanent magnet synchronous linear motor. The permanent magnet synchronous linear motor directly drives the vehicle-mounted permanent magnet module 202 to move laterally along the guide rod 2055.

[0060] The control module is used to control the linear drive mechanism 205 to operate based on the lateral displacement collected by the first displacement sensor 203 or the lateral displacement collected by the first displacement sensor 203 and the second displacement sensor, so that the vehicle-mounted permanent magnet module 202 is always kept at a specific working point on the permanent magnet track 3, eliminating the lateral force on the vehicle-mounted permanent magnet module 202 due to lateral offset, realizing zero-power stable suspension under undisturbed conditions, and even using the lateral force to return the bogie 1 to the center of the track, and can pass through curved tracks.

[0061] The control module determines whether the permanent magnet levitation system 2 is in levitation mode, levitation mode, or suspension mode based on commands (such as levitation command and levitation drop command) sent by the train control system. When the permanent magnet levitation system 2 is in levitation mode, applying a levitation command will enter levitation mode; when the permanent magnet levitation system 2 is in suspension mode, applying a levitation command will enter levitation mode. If the train is in levitation mode, a levitation command cannot be applied, nor can it be set to suspension mode; if the train is in suspension mode, a levitation command cannot be applied, nor can it be set to levitation mode.

[0062] When the permanent magnet levitation system 2 is in the levitation mode, it is assumed that the vehicle-mounted permanent magnet module 202 is located at the extreme position on one side of the center line of the permanent magnet track 3 (i.e., the maximum lateral displacement of the vehicle-mounted permanent magnet module 202 relative to the permanent magnet track 3). Based on the lateral displacement collected by the first displacement sensor 203, the linear drive mechanism 205 is controlled to move linearly, which drives the vehicle-mounted permanent magnet module 202 to move laterally. As the levitation time increases, the lateral displacement collected by the first displacement sensor 203 gradually approaches zero. That is, as the levitation time increases, the lateral displacement or lateral offset of the vehicle-mounted permanent magnet module 202 relative to the permanent magnet track 3 decreases to zero. At this time, the system state is set to the levitation state.

[0063] When the permanent magnet levitation system 2 is in levitation mode and no guide devices are installed on both sides of the bogie 1 (e.g.) Figure 5 As shown, when the permanent magnet levitation system 2 is only installed at the bottom of the bogie 1, and there are no guide devices on both sides of the bogie 1, a two-stage PID controller is used to control the linear drive mechanism 205 to operate based on the lateral displacement collected by the first displacement sensor 203 and the second displacement sensor. The lateral force received by the on-board permanent magnet module 202 is used to return the bogie 1 to the center of the track. Specifically:

[0064] The lateral displacement collected by the second displacement sensor is input to the first-stage PID controller to obtain the first control quantity. The difference between the first control quantity and the lateral displacement collected by the first displacement sensor 203 is input to the second-stage PID controller to obtain the second control quantity. The linear drive mechanism 205 is controlled to operate according to the second control quantity, using the lateral force on the on-board permanent magnet module 202 to return the bogie 1 to the track center. That is, it is expected to generate a force in the opposite direction to the bogie 1's deviation from the track center to return the bogie 1 to the track center. The track center refers to the center of the entire train's running track, not the center of the permanent magnet track 3.

[0065] When the permanent magnet levitation system 2 is in levitation mode and guide devices are installed on both sides of the bogie 1 (such as... Figures 6-8 As shown, when the guiding devices on both sides of the bogie 1 are the permanent magnet levitation system 2, electromagnet 7, and guide wheel 9 respectively, the linear drive mechanism 205 is controlled to operate according to the lateral displacement collected by the first displacement sensor 203, so that the lateral displacement collected by the first displacement sensor 203 is zero. That is, the linear drive mechanism 205 controls the vehicle permanent magnet module 202 to always stay at a specific working point of the permanent magnet track 3 (that is, the center of the vehicle permanent magnet module 202 coincides with the center of the permanent magnet track 3, and the lateral displacement between the vehicle permanent magnet module 202 and the permanent magnet track 3 is zero), eliminating the lateral force on the vehicle permanent magnet module 202 due to lateral offset, reducing the load on the electromagnetic guiding device or mechanical guiding device, and realizing zero-power stable levitation.

[0066] When the permanent magnet levitation system 2 is in levitation mode and guide devices are installed on both sides of the bogie 1, a two-stage PID controller is used to control the linear drive mechanism 205. The first control quantity output by the first-stage PID controller is zero. The difference between zero and the lateral displacement collected by the first displacement sensor 203 is input to the second-stage PID controller to obtain the second control quantity. The linear drive mechanism 205 is controlled to move according to the second control quantity to keep the lateral displacement between the vehicle-mounted permanent magnet module 202 and the permanent magnet track 3 at zero.

[0067] When the permanent magnet levitation system 2 is in the levitation mode, the linear drive mechanism 205 is controlled to operate according to the lateral displacement collected by the first displacement sensor 203, so that the lateral displacement collected by the first displacement sensor 203 increases until the repulsive force between the on-board permanent magnet module 202 and the permanent magnet track 3 is reduced to an insufficient level to support the levitation of the train. The on-board permanent magnet module 202 is located at the extreme position on one side of the center line of the permanent magnet track 3 (that is, the maximum lateral displacement of the on-board permanent magnet module 202 relative to the permanent magnet track 3), thus realizing the levitation of the train.

[0068] Example 2

[0069] like Figure 4 As shown, this embodiment of the invention provides a control method for a permanent magnet levitation system 2 as described in Embodiment 1, comprising the following steps:

[0070] Step 1: Acquire the lateral displacement collected by the first displacement sensor 203 and the second displacement sensor, and acquire the instructions from the train control system.

[0071] Step 2: Determine the working mode of the permanent magnet levitation system 2 according to the instructions sent by the train control system. The working modes include buoyancy mode, suspension mode and buoyancy mode.

[0072] Step 3: When the permanent magnet levitation system 2 is in the levitation mode, the linear drive mechanism 205 is controlled to move linearly according to the lateral displacement collected by the first displacement sensor 203, which drives the vehicle-mounted permanent magnet module 202 to move laterally. As the levitation time increases, the lateral displacement collected by the first displacement sensor 203 gradually approaches zero. That is, as the levitation time increases, the lateral displacement or lateral offset of the vehicle-mounted permanent magnet module 202 relative to the permanent magnet track 3 decreases to zero.

[0073] Step 4: When the permanent magnet levitation system 2 is in levitation mode and no guide devices are installed on both sides of the bogie 1 (e.g. Figure 5 As shown, when the permanent magnet levitation system 2 is only installed at the bottom of the bogie 1, and there are no guide devices on both sides of the bogie 1, a two-stage PID controller is used to control the linear drive mechanism 205 to operate based on the lateral displacement collected by the first displacement sensor 203 and the second displacement sensor. The lateral force received by the on-board permanent magnet module 202 is used to return the bogie 1 to the center of the track. Specifically:

[0074] The lateral displacement collected by the second displacement sensor is input to the first-stage PID controller to obtain the first control quantity; the difference between the first control quantity and the lateral displacement collected by the first displacement sensor 203 is input to the second-stage PID controller to obtain the second control quantity; the linear drive mechanism 205 is controlled to operate according to the second control quantity, and the lateral force received by the on-board permanent magnet module 202 is used to make the bogie 1 return to the center of the track, that is, it is expected to generate a force in the opposite direction to the bogie 1 deviating from the center of the track to make the bogie 1 return to the center of the track.

[0075] Step 5: When the permanent magnet levitation system 2 is in levitation mode and guide devices are installed on both sides of the bogie 1 (such as...) Figures 6-8 As shown, when the guide devices on both sides of the bogie 1 are the permanent magnet levitation system 2, the electromagnet 7, and the guide wheel 9 respectively, the linear drive mechanism 205 is controlled to operate according to the lateral displacement collected by the first displacement sensor 203, so that the lateral displacement collected by the first displacement sensor 203 is zero. That is, the linear drive mechanism 205 controls the vehicle-mounted permanent magnet module 202 to always remain at a specific working point of the permanent magnet track 3 (that is, the center of the vehicle-mounted permanent magnet module 202 coincides with the center of the permanent magnet track 3, and the lateral displacement between the vehicle-mounted permanent magnet module 202 and the permanent magnet track 3 is zero).

[0076] Step 6: When the permanent magnet levitation system 2 is in the levitation mode, the linear drive mechanism 205 is controlled to move according to the lateral displacement collected by the first displacement sensor 203, so that the lateral displacement collected by the first displacement sensor 203 increases until the repulsive force between the on-board permanent magnet module 202 and the permanent magnet track 3 is reduced to be insufficient to support the levitation of the train. The on-board permanent magnet module 202 is located at the extreme position on one side of the center line of the permanent magnet track 3 (that is, the maximum lateral displacement of the on-board permanent magnet module 202 on the linear guide rail), thus realizing the levitation of the train.

[0077] When the permanent magnet levitation system 2 is in the lifting mode, suspension mode, and levitation-dropping mode, the linear drive mechanism 205 can be controlled by a two-stage cascaded PID controller based on the lateral displacement collected by the first displacement sensor 203 or the lateral displacement collected by the first displacement sensor 203 and the second displacement sensor. When the permanent magnet levitation system 2 is in suspension mode and there are no guide devices on both sides of the bogie 1, the first control quantity output by the first-stage PID controller is obtained based on the lateral displacement collected by the second displacement sensor. In other operating modes (lifting mode, levitation-dropping mode, and suspension mode with guide devices on both sides of the bogie 1), the first control quantity output by the first-stage PID controller is zero.

[0078] The control module converts the second control quantity output by the second-stage PID controller into a control command. The linear drive mechanism 205 operates under the control command, which can be drive current (for permanent magnet synchronous motors), rotation angle (for stepper motors), or displacement (for linear motors).

[0079] Example 3

[0080] This invention also provides a maglev train, wherein a permanent magnet levitation system 2 as described in Embodiment 1 is provided at the bottom of the bogie 1 of the maglev train, and no guide devices (such as guides) are provided on both sides of the bogie 1. Figure 5(as shown); or, a permanent magnet levitation system 2 as described in Embodiment 1 is provided at the bottom of the bogie 1 of the maglev train, and guide devices (such as...) are provided on both sides of the bogie 1. Figures 6-8 (As shown).

[0081] In this embodiment, the guiding device is the permanent magnet levitation system 2 as described above (e.g., Figure 6 (as shown) or electromagnet 7 (such as) Figure 7 (as shown) or guide wheel 9 (as shown) Figure 8 (as shown); when the guiding device is an electromagnet 7, a ferromagnetic track plate 8 is set on the track beam 6 and the ferromagnetic track plate 8 corresponds to the electromagnet 7; when the guiding device is a guide wheel 9, the guide wheel 9 contacts the track beam 6.

[0082] like Figure 5 As shown, a permanent magnet levitation system 2 is installed at the bottom of the bogie 1. The permanent magnet levitation system 2, together with the car body 4 and the permanent magnet track 3 on the track beam 6, forms a permanent magnet levitation vehicle-track system. In the levitation state, the permanent magnet levitation system 2 mainly operates in active guidance mode. In this mode, both the levitation force and the guiding force are provided by the permanent magnet levitation system 2. When the bogie 1 deviates from the center of the track, the second displacement sensor collects the lateral displacement or lateral offset. The lateral displacement collected by the second displacement sensor is input to the first-stage PID controller to obtain the first control quantity. The difference between the first control quantity and the lateral displacement collected by the first displacement sensor 203 is input to the second-stage PID controller to obtain the second control quantity. According to the second control quantity, the linear drive mechanism 205 is controlled to move, causing the on-board permanent magnet module 202 to move in the opposite direction. After crossing the center line of the magnetic track, it receives a force opposite to the offset direction of the bogie 1, which can make the bogie 1 return to the center of the track. Although the vehicle-mounted permanent magnet module 202 will be subjected to a lateral force in the same direction as the offset before crossing the center of the permanent magnet track 3 during this process, and this lateral force will be transmitted to the bogie 1, this lateral force will not be immediately applied to the vehicle body 4 and will be partially consumed due to the lateral damping between the bogie 1 and the car body 4 (e.g., the lateral suspension mechanism 101 with hydraulic shock absorbers). Therefore, the scheme is theoretically feasible.

[0083] The active guidance mode places high demands on the response speed of the control system. To reduce the requirements on the control system, guidance devices are installed on both sides of the bogie 1. In this embodiment, the guidance device can be a permanent magnet levitation system 2, an electromagnet 7, or a guide wheel 9.

[0084] like Figure 6As shown, in addition to the permanent magnet levitation system 2 installed at the bottom of the bogie 1, permanent magnet levitation systems 2 are also installed on both sides of the bogie 1. The permanent magnet levitation system 2 corresponds to the permanent magnet track 3, so the permanent magnet track 3 is also installed on the side wall of the track beam 6. In the levitation state, the permanent magnet levitation system 2 works in the centering mode, that is, it controls the linear drive mechanism 205 to move according to the lateral displacement collected by the first displacement sensor 203, so that the lateral displacement collected by the first displacement sensor 203 is zero, realizing the centering of the vehicle-mounted permanent magnet module 202 with the corresponding permanent magnet track 3. After centering, the vehicle-mounted permanent magnet module 202 will only be subjected to the normal force (that is, the force perpendicular to the surface of the vehicle-mounted permanent magnet module 202), generating pure levitation force and guiding force respectively.

[0085] Considering Figure 6 The proposed solution requires the addition of two more permanent magnet tracks 3, which increases costs. To reduce costs, electromagnets 7 are used as the guiding device. Figure 7 As shown, in addition to the permanent magnet levitation system 2 installed at the bottom of the bogie 1, electromagnets 7 are installed on both sides of the bogie 1, and ferromagnetic track plates 8 are installed at corresponding positions on the sidewalls of the track beam 6. In the levitation state, the permanent magnet levitation system 2 operates in centering mode, that is, it controls the linear drive mechanism 205 to operate based on the lateral displacement collected by the first displacement sensor 203, making the lateral displacement collected by the first displacement sensor 203 zero, thus achieving centering between the onboard permanent magnet module 202 and the permanent magnet track 3, generating only levitation force. The guiding force is provided by the electromagnetic force of the electromagnets 7, and the magnitude of the guiding force is controlled by the levitation system collecting the gap between the electromagnets 7 and the ferromagnetic track plates 8, adjusting the current according to the gap. Compared with existing electromagnetically guided permanent magnet levitation vehicles, Figure 7 The proposed solution can significantly reduce the load on the guide electromagnet and lower power consumption.

[0086] To further reduce costs and complexity, mechanical guide wheels 9 are used as the guiding device. For example... Figure 8 As shown, in addition to the permanent magnet levitation system 2 installed at the bottom of the bogie 1, guide wheels 9 are installed on both sides of the bogie 1. In the levitation state, the permanent magnet levitation system 2 operates in centering mode, that is, it controls the linear drive mechanism 205 to operate based on the lateral displacement collected by the first displacement sensor 203, making the lateral displacement collected by the first displacement sensor 203 zero, thus achieving centering between the onboard permanent magnet module 202 and the permanent magnet track 3, generating only levitation force. The guiding force is provided by the contact force between the guide wheels 9 and the track beam 6. Compared with existing mechanically guided permanent magnet levitation vehicles, Figure 8 The proposed solution can significantly reduce the load on the guide wheel, thereby reducing the frictional resistance and noise generated by the guide wheel.

[0087] The above description only discloses specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A permanent magnet levitation system, characterized in that, The system includes: Framework basics; A linear drive mechanism based on the aforementioned frame; An on-board permanent magnet module is mounted on the linear drive mechanism, and the magnetic poles of the on-board permanent magnet module are opposite to those of the permanent magnet track; A first displacement sensor used to collect the lateral displacement between the vehicle-mounted permanent magnet module and the permanent magnet track; A second displacement sensor used to collect the lateral displacement of the bogie relative to the center of the track; A control module is connected to the linear drive mechanism, the first displacement sensor, and the second displacement sensor respectively. The control module is used to eliminate the lateral force on the on-board permanent magnet module based on the lateral displacement collected by the first displacement sensor, or to control the linear drive mechanism to move based on the lateral displacement collected by the first displacement sensor and the second displacement sensor so that the bogie returns to the center of the track.

2. The permanent magnet levitation system according to claim 1, characterized in that: The vehicle-mounted permanent magnet module uses a Halbach array.

3. The permanent magnet levitation system according to claim 1, characterized in that: The frame base is an inverted U-shaped structure, with a dust cover at the opening of the inverted U-shaped structure. The linear drive mechanism, the vehicle-mounted permanent magnet module, and the first displacement sensor are located in the cavity formed by the inverted U-shaped structure and the dust cover.

4. The permanent magnet levitation system according to any one of claims 1 to 3, characterized in that: The linear drive mechanism includes a linear guide rail and a linear drive device; the linear guide rail includes a guide rod and a slider, the guide rod is fixed on the frame foundation, the slider is slidably disposed on the guide rod, the vehicle-mounted permanent magnet module is disposed on the slider, and the linear drive device is connected to the vehicle-mounted permanent magnet module.

5. The permanent magnet levitation system according to claim 4, characterized in that: The linear drive device includes a drive motor and a lead screw and nut mechanism. The output end of the drive motor is connected to the lead screw of the lead screw and nut mechanism, and the lead screw and nut mechanism is connected to the vehicle-mounted permanent magnet module.

6. The permanent magnet levitation system according to claim 4, characterized in that: The linear drive device is a synchronous belt drive mechanism, which includes a driving pulley, a driven pulley, a synchronous belt wound around the driving pulley and the driven pulley, and a drive motor. The driving pulley and the driven pulley are fixed on the frame foundation, the output end of the drive motor is connected to the driving pulley, and the synchronous belt is connected to the vehicle-mounted permanent magnet module through a pressure plate.

7. A control method for a permanent magnet levitation system as described in any one of claims 1 to 6, characterized in that, The control method includes the following steps: When the permanent magnet levitation system is in the levitation mode, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor is zero. When the permanent magnet levitation system is in the levitation mode, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor increases until the repulsive force between the on-board permanent magnet module and the permanent magnet track is reduced to a level that is insufficient to support the levitation of the train. When the permanent magnet levitation system is in levitation mode and there are no guide devices on both sides of the bogie, the linear drive mechanism is controlled to move according to the lateral displacement collected by the first displacement sensor and the second displacement sensor, and the bogie is returned to the center of the track by the lateral force on the on-board permanent magnet module. When the permanent magnet levitation system is in levitation mode and guide devices are installed on both sides of the bogie, the linear drive mechanism is controlled to operate based on the lateral displacement collected by the first displacement sensor, so that the lateral displacement collected by the first displacement sensor is zero.

8. The control method for the permanent magnet levitation system according to claim 7, characterized in that, When the permanent magnet levitation system is in levitation mode and there are no guide devices on both sides of the bogie, a two-stage PID controller is used to control the linear drive mechanism, specifically: The lateral displacement collected by the second displacement sensor is input to the first-stage PID controller to obtain the first control quantity; The difference between the first control quantity and the lateral displacement collected by the first displacement sensor is input to the second-stage PID controller to obtain the second control quantity; The linear drive mechanism is controlled by the second control quantity, and the bogie is returned to the center of the track by the lateral force on the on-board permanent magnet module.

9. A maglev train, characterized in that, The bottom of the bogie of the maglev train is provided with a permanent magnet levitation system as described in any one of claims 1 to 6, and no guide devices are provided on both sides of the bogie; Alternatively, the bottom of the bogie of the maglev train is provided with a permanent magnet levitation system as described in any one of claims 1 to 6, and guide devices are provided on both sides of the bogie.

10. The maglev train according to claim 9, characterized in that: The guiding device is an electromagnet or a guide wheel; When the guiding device is an electromagnet, a ferromagnetic track plate is set on the track beam and the ferromagnetic track plate corresponds to the electromagnet; when the guiding device is a guide wheel, the guide wheel contacts the track beam.

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