Active compensation type magnetic suspension rotor supporting system, position compensation method and application of active compensation type magnetic suspension rotor supporting system

Abstract

The invention discloses an active compensation type magnetic suspension rotor supporting system, a compensation method and application of the active compensation type magnetic suspension rotor supporting system, the active compensation type magnetic suspension rotor supporting system comprises a rotor shaft, the rotor shaft is rotatably installed in a machine shell through a magnetic suspension bearing assembly, the magnetic suspension bearing assembly comprises a radial magnetic suspension bearing and an axial magnetic suspension bearing, the radial magnetic suspension bearing is fixed in the machine shell, and the axial magnetic suspension bearing is fixed in the machine shell. The rotor shaft penetrates through the radial magnetic suspension bearing and the axial magnetic suspension bearing, a thrust disc is fixedly installed on the rotor shaft, the axial magnetic suspension bearing is adjacent to the thrust disc, the active axial position compensation device is further included, the axial magnetic suspension bearing can be installed in the machine shell in an axial moving mode, and the axial magnetic suspension bearing can be installed in the machine shell in an axial moving mode. The active axial position compensation device can adjust and compensate the axial position of the axial magnetic suspension bearing according to the telescopic change of the rotor shaft under different temperature conditions.

Description

Technical Field

[0001] The present invention relates to a magnetic levitation rotor support system, and particularly to an active compensation type magnetic levitation rotor support system, a compensation method and their applications. Background Art

[0002] The magnetic levitation rotor support system is electromagnetic levitation technology. Through magnetic force, there is no contact suspension between the rotor and the stator, which greatly reduces the friction when the rotor shaft rotates, reduces the loss of mechanical energy due to friction, and has a higher energy conversion rate.

[0003] Chinese Patent Publication No. CN118499254A discloses a magnetic levitation air compressor, including: a compressor housing, a motor stator, a rotor, a first impeller assembly and a second impeller assembly that can be subjected to axial magnetic force, and a control module. The compressor housing, the motor stator and the rotor are sleeved in sequence. Both ends of the rotor are rotatably connected to the inside of the compressor housing through magnetic levitation bearing groups. The first impeller assembly and the second impeller assembly are relatively fixedly installed at both ends of the rotor respectively; the magnetic levitation bearing groups include: a first thrust bearing member that generates a first axial magnetic force on the first impeller assembly, and a second thrust bearing member that generates a second axial magnetic force on the second impeller assembly. The vector sum of the first axial magnetic force and the second axial magnetic force is used to offset the axial force received by the rotor.

[0004] The above patent realizes the suspension of the rotor without physical contact with bearings or other components, greatly improving the energy conversion rate. However, since the rotor shaft will generate hysteresis eddy current loss from the stationary standby state to different rotational speed states, the stator assembly will generate copper loss, and the impeller will generate air flow friction loss. These losses will cause corresponding temperature changes, and the length of the rotor shaft will change due to the changes in thermal stress and mechanical stress. After the length of the rotor shaft changes, the position of the thrust disk on the rotor shaft will also change accordingly. However, due to the settings of the first thrust bearing member and the second thrust bearing member, the axial displacement of the thrust disk is restricted, resulting in the rotor shaft stretching left and right from the thrust disk, which will cause the misalignment of the radial magnetic levitation bearing and the rotor shaft, thereby affecting and weakening the electromagnetic bearing capacity of the magnetic levitation bearing. At the same time, if the rotor shaft stretches forward from the thrust disk, it will cause the change of the gap between the impeller and the volute, thereby affecting the work efficiency of the impeller, and seriously, there will be rubbing between the impeller and the volute; thus, it is urgently needed to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide an active compensation type magnetic levitation rotor support system, a compensation method and their applications for the above problems, so as to solve the problems raised in the above background art.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] An active compensation type magnetic levitation rotor support system, comprising a rotor shaft, the rotor shaft is rotatably installed in a casing through a magnetic levitation bearing assembly, the magnetic levitation bearing assembly includes a radial magnetic levitation bearing and an axial magnetic levitation bearing, the radial magnetic levitation bearing is fixed in the casing, the rotor shaft passes through the radial magnetic levitation bearing and the axial magnetic levitation bearing, and a target disk and a thrust disk are fixedly installed on the rotor shaft, the axial magnetic levitation bearing is adjacent to the thrust disk, and further includes an active axial position compensation device, the axial magnetic levitation bearing is axially movably installed in the casing, and the active axial position compensation device can adjust and compensate the axial position of the axial magnetic levitation bearing according to the telescopic change amount of the rotor shaft under different temperature conditions.

[0008] As a preferred embodiment of the present invention, the active axial position compensation device includes a temperature controller, a first active compensation component, and a second active compensation component. The axial magnetic levitation bearing includes a first axial magnetic levitation bearing arranged at the front end of the thrust disk in the axial direction and a second axial magnetic levitation bearing arranged at the rear end of the thrust disk in the axial direction. The first active compensation component is located at the front end of the first axial magnetic levitation bearing in the axial direction and is adjacent to the first axial magnetic levitation bearing. The second active compensation component is located at the rear end of the second axial magnetic levitation bearing in the axial direction and is adjacent to the second axial magnetic levitation bearing.

[0009] As a preferred embodiment of the present invention, the first active compensation component and the second active compensation component have the same structure and specifically include a heating sheet, a first metal sheet, and a second metal sheet. The heating sheet is electrically connected to the temperature controller. The first metal sheet and the second metal sheet are both made of shape memory alloy, and the thermal expansion coefficient of the first metal sheet is greater than that of the second metal sheet.

[0010] As a preferred embodiment of the present invention, the active axial position compensation device further includes a limiting component, the limiting component is fixed in the casing, and the limiting component is located at the rear end of the second active compensation component in the axial direction.

[0011] As a preferred embodiment of the present invention, a temperature sensor electrically connected to the temperature controller is arranged in the casing, and a position sensor for detecting the position of the target disk is arranged in the casing, and the position sensor is electrically connected to the temperature controller.

[0012] As a preferred embodiment of the present invention, a guide rail is arranged on the inner wall of the casing, the guide rail is arranged along the axial direction, and the first axial magnetic levitation bearing and the second axial magnetic levitation bearing are both slidably connected to the guide rail.

[0013] A position compensation method for a magnetic levitation rotor support system, the position compensation method comprising:

[0014] S1. Detect the position of the target disk on the rotor shaft, calculate the displacement of the target disk, detect the temperature inside the housing, and obtain the temperature value;

[0015] S2. Calculate the position compensation amount by combining the displacement of the target disk and the temperature value;

[0016] S3. Calculate the input current value of the heating sheet according to the position compensation amount, and output the corresponding temperature control current to the heating sheet;

[0017] S4. Detect the positions of the first axial magnetic levitation bearing and the second axial magnetic levitation bearing, calculate the displacement of the first axial magnetic levitation bearing and the displacement of the second axial magnetic levitation bearing, and determine whether the displacement of the first axial magnetic levitation bearing and the displacement of the second axial magnetic levitation bearing are the same as the displacement of the target disk. If so, execute step S5; if not, return to step S1;

[0018] S5. After the working condition is stable, detect the current values of the first axial magnetic levitation bearing and the second axial magnetic levitation bearing, compare the differences between the current values of the first axial magnetic levitation bearing, the second axial magnetic levitation bearing and the theoretical current value of the axial magnetic levitation bearing. If the difference > 1, return to step S1; if the difference ≤ 1, determine that the position compensation is successful.

[0019] A rotor support system for a magnetic levitation centrifugal blower, comprising an active compensation type magnetic levitation rotor support system as described above.

[0020] A rotor support system for a magnetic levitation centrifugal compressor, comprising an active compensation type magnetic levitation rotor support system as described above.

[0021] A rotor support system for a magnetic levitation centripetal turbo generator, comprising an active compensation type magnetic levitation rotor support system as described above.

[0022] The beneficial effects of the present invention are that, compared with the prior art, by adding an active axial position compensation device, the present invention can adjust and compensate the position of the axial magnetic levitation bearing under different temperature fields, ensure the stability of the relative position between the axial magnetic levitation bearing and the rotor shaft, reduce the influence of the expansion and contraction amount of the rotor shaft under different temperature fields on the electromagnetic force of the axial magnetic levitation bearing, and also reduce the influence on the gap between the impeller and the volute, so as to ensure the system efficiency and reliability of the magnetic levitation impeller machine under different working conditions. Description of the Drawings

[0023] Figure 1 It is a structural schematic diagram of an active compensation type magnetic levitation rotor support system, compensation method and its application of the present invention;

[0024] Figure 2 This is a schematic structural diagram of the active axial position compensation device of the present invention.

[0025] Figure 3 This is a flowchart of the position compensation method of the present invention.

[0026] In the figure:

[0027] 101, housing; 102, rotor shaft; 103, thrust disk; 104, front radial magnetic suspension bearing; 105, rear radial magnetic suspension bearing; 106, volute; 107, front end cover; 108, rear end cover; 109, impeller; 110, first axial magnetic suspension bearing; 111, second axial magnetic suspension bearing; 112, stator assembly; 113, permanent magnet core; 114, first metal sheet; 115, second metal sheet; 116, limiting component; 117, guide rail; 118, temperature sensor; 119, heating sheet. Detailed implementation manners

[0028] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a mechanical connection, an electrical connection, or can be indirectly connected through an intermediate medium, or can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the description of the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature not being in direct contact but being in contact through another feature therebetween. Moreover, the first feature being "above", "above", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below", and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature. The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation manners.

[0031] Please refer to Figures 1 to 3 as shownFigure 1 Structural schematic diagram of an active compensation type magnetic levitation rotor support system, compensation method and its application according to the present invention; Figure 2 Structural schematic diagram of an active axial position compensation device according to the present invention. Figure 3 Flow chart of the position compensation method according to the present invention.

[0032] In this embodiment, an active compensation type magnetic levitation rotor support system is applied to a magnetic levitation centrifugal compressor. The magnetic levitation centrifugal compressor includes a casing 101, a volute 106, a front end cover 107, a rear end cover 108, a stator assembly 112, an impeller 109 and a rotor shaft 102. The rotor shaft 102 is rotatably installed in the casing 101 through a magnetic levitation bearing assembly. The magnetic levitation bearing assembly includes a radial magnetic levitation bearing and an axial magnetic levitation bearing. The radial magnetic levitation bearing is fixed in the casing 101. The rotor shaft 102 passes through the radial magnetic levitation bearing and the axial magnetic levitation bearing, and a target disc and a thrust disc 103 are fixedly installed on the rotor shaft 102. The axial magnetic levitation bearing is adjacent to the thrust disc 103. An active axial position compensation device is further included. The axial magnetic levitation bearing is axially movably installed in the casing 101. The active axial position compensation device can adjust and compensate the axial position of the axial magnetic levitation bearing according to the telescopic change amount of the rotor shaft 102 under different temperature conditions.

[0033] Specifically, in this embodiment, the active axial position compensation device includes a temperature controller, a first active compensation component and a second active compensation component. The axial magnetic levitation bearing includes a first axial magnetic levitation bearing 110 arranged at the front end of the thrust disc 103 in the axial direction and a second axial magnetic levitation bearing 111 arranged at the rear end of the thrust disc 103 in the axial direction. The first active compensation component is located at the front end of the first axial magnetic levitation bearing 110 in the axial direction and is adjacent to the first axial magnetic levitation bearing 110. The second active compensation component is located at the rear end of the second axial magnetic levitation bearing 111 in the axial direction and is adjacent to the second axial magnetic levitation bearing 111.

[0034] Specifically, in this embodiment, the first active compensation component and the second active compensation component have the same structure, and specifically include a heating sheet 119, a first metal sheet 114 and a second metal sheet 115. The heating sheet 119 is electrically connected to the temperature controller. The first metal sheet 114 and the second metal sheet 115 are both made of shape memory alloy, and the thermal expansion coefficient of the first metal sheet 114 is greater than that of the second metal sheet 115.

[0035] Specifically, in this embodiment, the active axial position compensation device further includes a limiting component 116, which is fixed inside the housing 101 and is located at the axial rear end of the second active compensation component.

[0036] Specifically, in this embodiment, a temperature sensor 118 electrically connected to the temperature controller is provided inside the housing 101, and a position sensor for detecting the position of the target disk is provided inside the housing 101, and the position sensor is electrically connected to the temperature controller.

[0037] Specifically, in this embodiment, a guide rail 117 is provided on the inner wall of the housing 101. The guide rail 117 is arranged in the axial direction, and both the first axial magnetic levitation bearing 110 and the second axial magnetic levitation bearing 111 are slidably connected to the guide rail 117.

[0038] Specifically, in this embodiment, the impeller 109 is arranged at the front end of the rotor shaft 102. The gaseous working medium enters the impeller working chamber from the air inlet passage and is discharged after being compressed and doing work by the impeller 109.

[0039] Specifically, in this embodiment, the stator assembly 112 is arranged on the inner wall of the housing 101. The stator assembly 112 includes a stator core and a stator coil. The stator coil is wound around the stator core. A permanent magnet core 113 is embedded in the rotor shaft 102, and the permanent magnet core 113 faces the stator assembly 112. When an alternating current passes through the stator assembly 112, a rotating magnetic field is generated, which forms an electromagnetic force with the permanent magnet core 113 of the rotor shaft 102, thereby converting electrical energy into mechanical energy.

[0040] Specifically, in this embodiment, the front radial magnetic levitation bearing 104 is arranged on the housing 101. The front end of the rotor shaft 102 passes through the front radial magnetic levitation bearing 104. When an alternating current passes through the front radial magnetic levitation bearing 104, an electromagnetic force is formed with the rotor shaft 102. Collaborating with the electromagnetic force formed by the rear radial magnetic levitation bearing 105 and the rotor shaft 102, the rotor shaft 102 is supported, so that the rotor shaft 102 is suspended and does not come into physical contact with bearings or other components, greatly reducing the friction when the rotor shaft 102 rotates, reducing the loss of mechanical energy due to friction, and having a higher energy conversion rate.

[0041] Specifically, in this embodiment, the thrust disk 103 is fixed on the rotor shaft 102. The first axial magnetic levitation bearing 110 is arranged at the front end of the thrust disk 103, and the second axial magnetic levitation bearing 111 is arranged at the rear end of the thrust disk 103. When the impeller 109 compresses and does work, an axial force will be generated. The axial force acts on the thrust disk 103. When the first axial magnetic levitation bearing 110 passes through an alternating current, the electromagnetic force formed acts on the thrust disk 103. When the second axial magnetic levitation bearing 111 passes through an alternating current, the electromagnetic force formed also acts on the thrust disk 103. Furthermore, acting forces are formed on both the front and rear sides of the thrust disk 103, thereby limiting the axial displacement of the rotor shaft 102.

[0042] A position compensation method for a magnetic levitation rotor support system, the position compensation method comprising:

[0043] S1. Detect the position of the target disk on the rotor shaft 102, calculate the displacement of the target disk, detect the temperature inside the housing 101, and obtain the temperature value;

[0044] S2. Calculate the position compensation amount by combining the target disk displacement amount and the temperature value;

[0045] S3. Calculate the input current value of the heating sheet 119 according to the position compensation amount, and output the corresponding temperature control current to the heating sheet 119;

[0046] S4. Detect the positions of the first axial magnetic levitation bearing 110 and the second axial magnetic levitation bearing 111, calculate the displacement amounts of the first axial magnetic levitation bearing 110 and the second axial magnetic levitation bearing 111, and determine whether the displacement amounts of the first axial magnetic levitation bearing 110 and the second axial magnetic levitation bearing 111 are the same as the target disk displacement amount. If so, execute step S5; if not, return to step S1;

[0047] S5. After the working conditions are stable, detect the current values of the first axial magnetic levitation bearing 110 and the second axial magnetic levitation bearing 111, compare the differences between the current values of the first axial magnetic levitation bearing 110, the current value of the second axial magnetic levitation bearing 111 and the theoretical current value of the axial magnetic levitation bearing. If the difference > 1, return to step S1; if the difference ≤ 1, determine that the position compensation is successful.

[0048] This embodiment adopts a dual-loop control strategy, namely an inner-loop control strategy and an outer-loop control strategy. Among them, the inner-loop control strategy outputs current to the heating sheet 119 according to the position of the target disk and the temperature inside the housing 101, and can control the temperature of the heating sheet 119, thereby deforming the first metal sheet 114 and the second metal sheet 115 to adjust the position of the compensated axial magnetic bearing, ensuring that the thrust disk 103 is located exactly in the middle of the first axial magnetic bearing 110 and the second axial magnetic bearing 111, and further ensuring the clearance between the impeller 109 and the volute 106; the outer-loop control strategy is to receive the axial magnetic bearing control current value transmitted by the host computer after the magnetic levitation impeller machinery condition is stable, calculate and correct the output current of the heating sheet 119 controlled by the inner loop, so as to minimize the difference in the axial magnetic bearing control current as much as possible and make the whole system more stable.

[0049] When the temperature changes and the position of the thrust disk 103 on the rotor shaft 102 has a tendency to change, the heating sheet 119 of the active axial position compensation device starts to heat up. The first metal sheet 114 and the second metal sheet 115 are deformed by heat, and push the first axial magnetic bearing 110 and the second axial magnetic bearing 111 to move axially, basically ensuring that the first magnetic bearing 110 and the second axial magnetic bearing 111 are directly opposite to the thrust disk 103, and the increase in the axial length of the first compensation component is equal to the decrease in the axial length of the second compensation component, thereby being able to maintain structural stability; for example, please refer to Figure 2 As shown, when the temperature rises, the heating sheet 119 starts to heat up. The first compensation component bends, and its center bulges to the right, and then pushes the first axial magnetic bearing 110 to move to the right. At the same time, the second compensation component bends, and its center bulges to the right. The first compensation component pushes the first axial magnetic bearing 110 to move, and then drives the thrust disk 103 to move. Since there is a repulsive force between the thrust disk 103 and the second axial magnetic bearing 111, it will drive the second axial magnetic bearing 111 to move. The movement amount of the first axial magnetic bearing 110 is equal to the extension amount of the thrust disk 103 after being heated, so as to avoid the rotor shaft 102 from elongating from the thrust disk 103 to both ends while ensuring the relative position stability of the first axial magnetic bearing 110, the second axial magnetic bearing 111 and the thrust disk 103; when the temperature drops, the first compensation component and the second compensation component slowly return to their original shapes. The second compensation component will push the second axial magnetic bearing 111 to move left and reset. Under the action of the repulsive force, it drives the thrust disk 103 to reset, and the thrust disk 103 drives the first axial magnetic bearing 110 to reset, still maintaining the relative position between the first axial magnetic bearing 110, the second axial magnetic bearing 111 and the thrust disk 103.

[0050] It is worth mentioning that although only the passive compensation type magnetic levitation rotor support system is described in this embodiment to be applied to a magnetic levitation centrifugal compressor, the present invention is not limited thereto. The passive compensation type magnetic levitation rotor support system can also be applied to a magnetic levitation centrifugal blower and a magnetic levitation inward flow turbine generator.

[0051] The above embodiments only illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, there are various changes and modifications to the present invention, and these changes and modifications all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims.

Claims

1. An active compensation type magnetic levitation rotor support system, comprising a rotor shaft, wherein the rotor shaft is rotatably installed in a casing through a magnetic levitation bearing assembly, the magnetic levitation bearing assembly includes a radial magnetic levitation bearing and an axial magnetic levitation bearing, the radial magnetic levitation bearing is fixed in the casing, the rotor shaft passes through the radial magnetic levitation bearing and the axial magnetic levitation bearing, and a target disk and a thrust disk are fixedly installed on the rotor shaft, the axial magnetic levitation bearing is adjacent to the thrust disk, and it is characterized in that: It further includes an active axial position compensation device. The axial magnetic suspension bearing is axially movably installed in the housing. The active axial position compensation device can adjust and compensate the axial position of the axial magnetic suspension bearing according to the telescopic change amount of the rotor shaft under different temperature conditions.

2. The active compensation type magnetic suspension rotor support system according to claim 1, characterized in that: The active axial position compensation device includes a temperature controller, a first active compensation component, and a second active compensation component. The axial magnetic suspension bearing includes a first axial magnetic suspension bearing arranged at the front end of the thrust disc in the axial direction and a second axial magnetic suspension bearing arranged at the rear end of the thrust disc in the axial direction. The first active compensation component is located at the front end of the first axial magnetic suspension bearing in the axial direction and is adjacent to the first axial magnetic suspension bearing. The second active compensation component is located at the rear end of the second axial magnetic suspension bearing in the axial direction and is adjacent to the second axial magnetic suspension bearing.

3. An active compensation type magnetic levitation rotor support system according to claim 2, characterized in that: The first active compensation component and the second active compensation component have the same structure and specifically include a heating sheet, a first metal sheet, and a second metal sheet. The heating sheet is electrically connected to the temperature controller. The first metal sheet and the second metal sheet are both made of shape memory alloy, and the thermal expansion coefficient of the first metal sheet is greater than that of the second metal sheet.

4. The active compensation type magnetic suspension rotor support system according to claim 3, characterized in that: The active axial position compensation device further includes a limiting component. The limiting component is fixed in the housing and is located at the rear end of the second active compensation component in the axial direction.

5. An active compensation type magnetic levitation rotor support system according to claim 4, characterized in that: A temperature sensor electrically connected to the temperature controller is arranged in the housing, and a position sensor for detecting the position of the target disc is arranged in the housing. The position sensor is electrically connected to the temperature controller.

6. An active compensation type magnetic levitation rotor support system according to any one of claims 1 to 5, characterized in that: Guide rails are arranged on the inner wall of the housing. The guide rails are arranged along the axial direction. The axial magnetic suspension bearing is slidably connected to the guide rails.

7. A position compensation method for a magnetic levitation rotor support system, characterized in that: The position compensation method includes: S1. Detect the position of the target disc on the rotor shaft, calculate the displacement of the target disc, detect the temperature in the housing, and obtain the temperature value; S2. Calculate the position compensation amount by combining the displacement of the target disc and the temperature value; S3. Calculate the input current value of the heating sheet according to the position compensation amount and output the corresponding temperature control current to the heating sheet; S4. Detect the positions of the first axial magnetic suspension bearing and the second axial magnetic suspension bearing, calculate the displacement of the first axial magnetic suspension bearing and the displacement of the second axial magnetic suspension bearing, and determine whether the displacement of the first axial magnetic suspension bearing and the displacement of the second axial magnetic suspension bearing are the same as the displacement of the target disc. If so, execute step S5. If not, return to step S1; S5. After the working condition is stable, detect the current values of the first axial magnetic suspension bearing and the second axial magnetic suspension bearing, compare the differences between the current values of the first axial magnetic suspension bearing, the current values of the second axial magnetic suspension bearing and the theoretical current value of the axial magnetic suspension bearing. If the difference > 1, return to step S1. If the difference ≤ 1, it is determined that the position compensation is successful.

8. A rotor support system for a magnetic levitation centrifugal blower, characterized in that: An active compensation type magnetic suspension rotor support system according to any one of claims 1 to 7.

9. A rotor support system for a magnetic levitation centrifugal compressor, characterized in that: An active compensation type magnetic suspension rotor support system according to any one of claims 1 to 7.

10. A rotor support system for a magnetic levitation centripetal turbine generator, characterized in that: An active compensation type magnetic suspension rotor support system according to any one of claims 1 to 7.

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