Magnetic bearing and control method and control system for controlling a magnetic bearing

Abstract

The application provides a magnetic bearing for magnetically connecting a rotatable component to a fixed component. The magnetic bearing includes a thrust plate, a coil, and a housing. The thrust plate is fixed to the rotatable component and extends radially relative thereto. The coil is axially spaced from the thrust plate and is configured to generate an electromagnetic force in an energized state to move the thrust plate axially toward the coil. The housing is fixed to the fixed component and houses the coil and includes an opening facing the thrust plate. The housing has a first coupling portion adjacent the opening and the thrust plate has a second coupling portion. An air gap is formed between the first coupling portion and the second coupling portion, and the air gap includes a first air gap portion configured to reduce a variation in the electromagnetic force generated by the coil over a predetermined range of axial positions of the thrust plate. The electromagnetic force variation is smooth to reduce or avoid control overshoot, to provide a larger electromagnetic force at axial positions away from the coil to speed up response and reduce loss and heat, and to obtain a wide linear range.

Description

Technical Field

[0001] This application relates to magnetic levitation bearings and control methods and control systems for controlling magnetic levitation bearings, and particularly to axial magnetic levitation bearings and control methods and control systems for controlling axial magnetic levitation bearings. Background Technology

[0002] Magnetic levitation bearings are highly effective for supporting rotating shafts and other objects, allowing them to float or levitate effectively using electromagnetic fields. This eliminates frictional contact between the rotating shaft and any fixed structure, enabling frictionless rotation of the shaft or rotation of objects around it. This arrangement offers significant advantages: no mechanical wear, resulting in reduced mechanical noise, and durability unmatched by other bearing types. Furthermore, because magnetic levitation bearings reduce the frictional effects common in traditional bearing structures, higher rotational speeds can be achieved.

[0003] A magnetic levitation bearing includes an axial magnetic levitation bearing, which uses electromagnetic force generated by an electromagnetic field to achieve contactless support along the axial direction of a rotatable object. It is used to bear the axial load of the rotatable object and maintains the axial position stability of the rotatable object through a control system. The axial magnetic levitation bearing can be applied to high-speed motors and magnetically levitated centrifugal compressors, for example, in applications requiring contactless axial support and high dynamic performance, such as refrigeration air conditioning, heat pumps, freezing, and compressed air systems. Summary of the Invention

[0004] Through long-term observation and research, the inventors discovered that existing axial magnetic bearings may have some problems when operating under heavy loads and a wide range of working conditions. For example, under given dimensions and power supply capacity, the output capacity of the axial electromagnetic force is relatively small, making it difficult to provide a sufficiently large axial load-bearing capacity. When the thrust plate fixed to the rotatable object is at its extreme offset position (i.e., the position farthest from the coil), a larger electromagnetic force must be obtained, which can easily lead to risks such as coil overheating. Furthermore, different axial positions of the thrust plate have a significant impact on the electromagnetic force generated by the coil under the same current, which can easily cause overshoot in the control process. Within a small axial position range of the thrust plate, the electromagnetic force generated by the coil is roughly linearly related to the axial position of the thrust plate, making it difficult for the control system to control stably, resulting in a narrow linear control range. Moreover, existing technologies typically require position sensors to estimate the thrust plate position to achieve closed-loop adjustment and control of the axial position. Position sensors not only occupy a large installation space but also have high requirements for the condition of the measured target (such as surface cleanliness). Therefore, the existing technology of stopping the push plate position detection relies on position sensors, which limits the accuracy under harsh working conditions (such as oil / vibration) and is not conducive to the miniaturization of magnetic levitation bearings.

[0005] To address the aforementioned problems, this application provides a magnetic levitation bearing that magnetically connects a rotatable component relative to a fixed component. A first coupling portion is provided on a housing fixed to the fixed component, and a second coupling portion is provided on a thrust plate fixed to the rotatable component. An air gap formed between the first and second coupling portions provides a substantially uniform gap with respect to the axial direction. During axial movement of the thrust plate, the change in gap provided by the air gap is small, for example, smaller than the change in the axial position of the thrust plate, resulting in a small change in the electromagnetic force generated by the coil, thus ensuring smooth electromagnetic force variation. By controlling the change in electromagnetic force within a predetermined value, the electromagnetic force generated by the coil is substantially linearly related to the axial position of the thrust plate over a large range of axial positions, thereby enabling the magnetic levitation bearing to achieve a wide linear range. When the thrust plate moves axially away from the coil, the electromagnetic force generated by the coil decreases. However, the increase in gap provided by the air gap is small, therefore the decrease in the electromagnetic force generated by the coil is small, i.e., the electromagnetic force remains relatively large. Therefore, compared to the prior art, the electromagnetic force generated by the coil in this application is greater at multiple axial positions of the thrust plate that are far from the coil.

[0006] Specifically, according to a first aspect of this application, a magnetic levitation bearing is provided for magnetically connecting a rotatable component relative to a fixed component. The magnetic levitation bearing includes a thrust plate, a coil, and a housing. The thrust plate is fixed to the rotatable component and extends radially relative to it. The coil is axially spaced from the thrust plate and configured to generate an electromagnetic force in an energized state, causing the thrust plate to move axially toward the coil. The housing is fixed to the fixed component, the housing accommodating the coil and including an opening toward the thrust plate. The housing has a first coupling portion adjacent to the opening, and the thrust plate has a second coupling portion. An air gap is formed between the first coupling portion and the second coupling portion, the air gap including a first air gap portion. The first air gap portion is configured to reduce the variation in the electromagnetic force generated by the coil within a predetermined axial position range of the thrust plate.

[0007] In some embodiments, the first air gap portion is configured to provide a generally uniform gap that is tilted relative to the axial direction.

[0008] In some embodiments, the air gap further includes a second air gap portion that extends substantially radially. The first air gap portion and the second air gap portion cooperate such that, within a predetermined axial position range of the thrust plate, the change in the electromagnetic force generated by the coil under a predetermined energizing current reaches a predetermined change value, and the electromagnetic force is substantially linearly related to the axial position of the thrust plate.

[0009] In some embodiments, the first coupling portion includes a first inclined surface and a first radially extending surface. The second coupling portion includes a second inclined surface and a second radially extending surface. The first inclined surface and the second inclined surface are substantially parallel to form the first air gap portion, and the first radial surface and the second radial surface are substantially parallel to form the second air gap portion.

[0010] In some embodiments, the first inclined surface forms a first angle f relative to the axial direction, and the second inclined surface forms a second angle e relative to the axial direction. The first angle f and the second angle e are approximately the same and are configured to adjust the amount of change in the clearance provided by the first air gap portion within a predetermined axial position range of the thrust plate.

[0011] In some embodiments, the first inclined surface has a first length d along the axial direction, and the second inclined surface has a second length c along the axial direction. The first length d and the second length c are configured to adjust the proportion of the electromagnetic field generated by the coil passing through the first air gap portion.

[0012] In some embodiments, the air gap further includes a third air gap portion configured to adjust the proportion of the electromagnetic field generated by the coil passing through the first air gap portion.

[0013] In some embodiments, the first coupling portion further includes a third inclined surface, and the second coupling portion further includes a third radial surface extending radially. A third air gap portion is formed between the third inclined surface and the third radial surface. The third inclined surface has a third length a along the axial direction and forms a third angle b relative to the axial direction; the third length a and the third angle b are configured to adjust the proportion of the electromagnetic field generated by the coil passing through the third air gap portion.

[0014] In some embodiments, the plurality of axial positions includes a plurality of axial positions away from the coil.

[0015] In some embodiments, within a predetermined axial position range of the thrust plate, the variation in the electromagnetic force generated by the coil under a plurality of predetermined energizing currents can be adjusted such that the inductance of the coil under the plurality of predetermined energizing currents has approximately the same linear relationship with the axial position of the thrust plate.

[0016] In some embodiments, the housing has two first coupling portions symmetrically arranged with respect to the opening. The thrust plate has two second coupling portions corresponding to the two first coupling portions.

[0017] In some embodiments, the coil is annular, and the housing has an annular groove for accommodating the coil.

[0018] According to a second aspect of this application, a control method is provided for controlling the aforementioned magnetic levitation bearing. The coil of the magnetic levitation bearing is energized by a drive unit. The control method includes: acquiring the inductance of the coil of the magnetic levitation bearing; obtaining the current axial position of the thrust plate based on the acquired inductance and the correlation between the inductance of the coil and the axial position of the thrust plate of the magnetic levitation bearing; and controlling the drive unit to energize the coil based on the obtained current axial position of the thrust plate, thereby controlling the movement of the thrust plate.

[0019] In some embodiments, the correlation includes: the inductance of the coil under a plurality of predetermined energizing currents is substantially linearly related to the axial position of the thrust plate.

[0020] In some embodiments, obtaining the inductance of the coil includes: sampling the bus voltage received by the driving unit to obtain a sampled bus voltage; sampling the current of the coil to obtain a sampled coil current; obtaining the inductive reactance of the coil based on the sampled bus voltage and coil current; and obtaining the inductance of the coil based on the inductive reactance of the coil.

[0021] In some embodiments, obtaining the inductive reactance of the coil includes: performing a low-pass filter on the sampled bus voltage to obtain a low-frequency component of the bus voltage; performing a high-pass filter on the sampled coil current to obtain a high-frequency component of the coil current; and obtaining the inductive reactance of the coil based on the low-frequency component of the bus voltage and the high-frequency component of the coil current.

[0022] According to a third aspect of this application, a control system is provided for controlling a magnetic levitation bearing. The control system includes a control device configured to perform the aforementioned control method to control the movement of the thrust plate of the magnetic levitation bearing.

[0023] In some embodiments, the control system further includes a rectifier unit, a drive unit, and a data acquisition device. The rectifier unit is configured to generate a bus voltage. The drive unit is configured to receive the bus voltage and drive the coil of the magnetic levitation bearing. The data acquisition device is configured to sample the bus voltage received by the drive unit to obtain a sampled bus voltage, and to sample the current of the coil to obtain a sampled coil current. The control device is configured to execute the control method based on the sampled bus voltage and coil current. Attached Figure Description

[0024] The accompanying drawings are not to scale. In the drawings, each identical or nearly identical component shown in different figures is indicated by the same reference numerals. For clarity, not every component may be labeled in every drawing. In the drawings: Figure 1A A perspective view of a magnetic levitation bearing according to an exemplary embodiment of this application is shown; Figure 1B It shows Figure 1A An exploded perspective view of the magnetic levitation bearing is shown. Figure 2A It shows Figure 1A A cross-sectional perspective view of the magnetic levitation bearing is shown. Figure 2B It shows Figure 2A A partial cross-sectional view of the magnetic levitation bearing is shown. Figure 2C It shows Figure 2B A magnified view of a portion of the image; Figure 2D It shows Figure 2A A partial schematic diagram of the electromagnetic field generated by the coil in the magnetic levitation bearing is shown. Figure 3A A cross-sectional perspective view of a magnetic levitation bearing according to another exemplary embodiment of this application is shown; Figure 3B It shows Figure 3A A partial cross-sectional view of the magnetic levitation bearing is shown. Figure 3C It shows Figure 3A A partial schematic diagram of the electromagnetic field generated by the coil in the magnetic levitation bearing is shown. Figure 4 A partial cross-sectional view of a magnetic levitation bearing according to another exemplary embodiment of this application is shown; Figures 5A-5F A partial cross-sectional view of a magnetic levitation bearing according to several exemplary embodiments of this application is shown; Figure 6 A schematic diagram showing the relationship between the electromagnetic force generated by the coil under a predetermined energizing current and the axial position of the thrust plate is shown. Figure 7 A schematic diagram showing the relationship between the inductance of the coil and the axial position of the thrust plate under a predetermined energizing current is shown. Figure 8 A structural block diagram of a control system for controlling a magnetic levitation bearing according to an exemplary embodiment of this application is shown; Figure 9 A flowchart illustrating a control method for controlling a magnetic levitation bearing according to an exemplary embodiment of this application is shown. Figure 10 It shows Figure 9 The detailed flowchart of step 902 shown; and Figure 11 It shows that according to Figure 8 The diagram shows the software structure of the control device. Detailed Implementation

[0025] Various specific embodiments of this application will now be described with reference to the accompanying drawings, which form part of this specification. It should be understood that, where possible, the same or similar reference numerals used in this application refer to the same parts.

[0026] Figure 1A A perspective view of a magnetic levitation bearing 100 according to an exemplary embodiment of this application is shown. Figure 1B It shows Figure 1A An exploded perspective view of the magnetic levitation bearing 100 is shown.

[0027] like Figure 1A and Figure 1B As shown, the magnetic bearing 100 magnetically connects the rotatable component 101 relative to the fixed component 102. In one embodiment, the rotatable component 101 is a rotatable shaft, such as a rotor. The fixed component 102 may include fixed components 102A and 102B. The magnetic bearing 100 includes a thrust plate 105, coils 104A and 104B, and housings 103A and 103B. Coils 104A and 104B may be collectively referred to as coil 104. Housings 103A and 103B may be collectively referred to as housing 103. The magnetic bearing 100 also includes the rotatable component 101 and the fixed component 102. These portions of the magnetic bearing 100 may be coaxially arranged. Housings 103A and 103B may be iron cores. Coils 104A and 104B may be energized to interact with housings 103A and 103B to generate axial electromagnetic forces for supporting and adjusting the axial position of the rotatable component 101 relative to the fixed component 102. In other embodiments, the housing comprises other suitable materials to perform the functions described above.

[0028] The thrust plate 105 is fixed to the rotatable member 101 and extends radially relative to the rotatable member 101. The coil 104A, housing 103A, and fixing member 102A are arranged substantially symmetrically with respect to the thrust plate 105 along the axial direction, and operate identically. The coil 104B, housing 103B, and fixing member 102B will now be described as an example. The coil 104B is axially spaced from the thrust plate 105 (along the direction of axis A). The coil 104B is configured to generate an electromagnetic force when energized, causing the thrust plate 105 to move axially toward the coil. The housing 103B is fixed to the fixing member 102B. The housing 103B is capable of accommodating the coil 104B and includes an opening 106 facing the thrust plate 105. The coil 104B is annular, and the housing 103B has an annular groove 107 for accommodating the coil 104B. An opening 106 is formed on the open side of the groove 107. The opening 106 is annular. The rotatable component 101 can pass through the annular housing 103B, the coil 104B, and the fixing component 102B.

[0029] In other embodiments, the magnetic levitation bearing may include other suitable structures to magnetically connect the rotatable component relative to the stationary component. For example, the magnetic levitation bearing may include a single coil and a single housing.

[0030] Figure 2A It shows Figure 1A The diagram shows a cross-sectional perspective view of the magnetic levitation bearing 100. Figure 2B It shows Figure 2A A partial cross-sectional view of the magnetic levitation bearing 100 is shown (where the fixing parts are omitted for clarity). Figure 2C It shows Figure 2B A magnified view of a portion of the image. Figure 2D It shows Figure 2A A partial schematic diagram of the electromagnetic field generated by the coil in the magnetic levitation bearing 100 is shown.

[0031] like Figure 2A As shown, during operation, currents of the same magnitude but opposite directions are passed through coils 104A and 104B to keep the thrust plate 105 and the rotatable component 101 substantially in a predetermined position, such as a central position. When the rotatable component 101 is subjected to an axial force applied by an external component, such as the pneumatic side of a compressor, causing the thrust plate 105 to shift towards coil 104A, the current flowing through coil 104B is increased. This causes coil 104B to generate a larger electromagnetic force that moves the thrust plate 105 towards it, counteracting the axial force of the external component and thus keeping the thrust plate 105 and the rotatable component 101 substantially in the predetermined position. Conversely, the same applies when the thrust plate 105 moves away from the predetermined position. During control, when the thrust plate 105 moves away from the predetermined position, the current in the corresponding coil is increased, increasing the electromagnetic force on the thrust plate 105 and causing it to move axially towards the predetermined position and towards the corresponding coil. As the thrust plate 105 approaches the predetermined position, the electromagnetic force generated by the corresponding coil gradually increases. At this time, it is necessary to reduce the current of the corresponding coil in a timely manner to stabilize the thrust plate 105 near the predetermined position. If the current of the coil is not properly controlled, the thrust plate 105 may easily overshoot the predetermined position.

[0032] like Figure 2A-2CAs shown, a first coupling portion 201 is provided on the housing 103, adjacent to an opening 106 in the housing 103 facing the thrust plate 105. A second coupling portion 202 is provided on the thrust plate 105. An air gap 203 is formed between the first coupling portion 201 and the second coupling portion 202. The electromagnetic field generated by the coil 104 passes through the air gap 203. The air gap 203 includes a first air gap portion 204, which is configured to reduce the amount of change in the electromagnetic force generated by the coil 104, for example, under a predetermined energizing current, within a predetermined axial position range of the thrust plate 105. The first air gap portion 204 is configured to provide a generally uniform gap inclined relative to the axial direction. During the axial movement of the thrust plate 105, the amount of change in the gap provided by the first air gap portion 204 is small, for example, smaller than the amount of change in the axial position of the thrust plate 105, thereby the amount of change in the electromagnetic force generated by the coil 104 on the thrust plate 105 is small, that is, the electromagnetic force changes smoothly. Smooth electromagnetic force changes can reduce or avoid overshoot in the control process. For example, within a predetermined axial position range of the thrust plate 105, when the change in the electromagnetic force generated by the coil 104 reaches a certain value, it can indicate that the electromagnetic force change is stable. This predetermined value can be less than or equal to a threshold value. Similarly, when the rate of change of the electromagnetic force generated by the coil 104 relative to the axial position of the thrust plate 105 reaches a predetermined rate of change, it can also indicate that the electromagnetic force change is stable. This predetermined rate of change can be less than or equal to a threshold value. In other embodiments, this application can indicate stable electromagnetic force changes using other suitable parameters.

[0033] As the thrust plate 105 moves axially from a position close to the coil 104 towards a position away from the coil 104, the electromagnetic force generated by the coil 104 gradually decreases. The change in the electromagnetic force generated by the coil 104 is small, ensuring that, over a wide range of axial positions of the thrust plate 105, the electromagnetic force generated by the coil 104 is approximately linearly related to the axial position of the thrust plate 105. In other words, this application achieves a wider linear range, making system control easier and more stable.

[0034] This application, by providing a gap in the first air gap portion 204, allows the coil 104 to generate a predetermined electromagnetic force, such as the required electromagnetic force, on the thrust plate 105 under a predetermined energizing current at an axial position close to (e.g., closest to, within a suitable range) the coil 104. Since the variation in the electromagnetic force generated by the coil 104 is small within the predetermined axial position range of the thrust plate 105, the reduction in the electromagnetic force generated by the coil 104 under the predetermined energizing current is small at multiple axial positions within the predetermined axial position range of the thrust plate 105 (e.g., including positions farthest from, especially furthest from, the axial position of the coil 104), thus the electromagnetic force generated by the coil 104 remains relatively large. At each predetermined energizing current, the electromagnetic force generated by the coil 104 is correspondingly large, thus requiring only a smaller current to generate the required electromagnetic force. Therefore, the magnetic bearing of this application can facilitate faster control response and reduce wear and heat generation in the magnetic bearing.

[0035] like Figure 2C As shown, the air gap 203 also includes a second air gap portion 205 that extends substantially radially. The first air gap portion 204 and the second air gap portion 205 cooperate such that, within a predetermined axial position range of the thrust plate 105, the change in the electromagnetic force generated by the coil 104 under a predetermined energizing current reaches a predetermined change value, and the electromagnetic force is approximately linearly related to the axial position of the thrust plate 105.

[0036] The first coupling portion 201 includes a first inclined surface 207 and a first radial surface 208 extending radially. The second coupling portion 202 includes a second inclined surface 209 and a second radial surface 210 extending radially. The first inclined surface 207 and the second inclined surface 209 are substantially parallel to form a first air gap portion 204, and the first radial surface 208 and the second radial surface 210 are substantially parallel to form a second air gap portion 205. The first inclined surface 207 forms a first angle f with respect to the axial direction, and the second inclined surface 209 forms a second angle e with respect to the axial direction. Both the first angle f and the second angle e are acute angles. In other embodiments, the degree of inclination of the first inclined surface 207 and the second inclined surface 209 with respect to the axial direction can also be represented by obtuse angles. The first angle f and the second angle e are substantially the same and are set to adjust the amount of change in the gap provided by the first air gap portion 204 within a predetermined axial position range of the thrust plate 105. The first inclined surface 207 has a first length d along the axial direction, and the second inclined surface 209 has a second length c along the axial direction. The first length d and the second length c are set to determine the proportion of the electromagnetic field generated by the coil 104 passing through the first air gap portion 204. The higher this proportion, the smaller the variation in the electromagnetic force generated by the coil 104, and the smoother the change in electromagnetic force. At multiple axial positions of the thrust plate 105 away from the coil 104, the electromagnetic force generated by the coil 104 is greater. In the embodiment shown in the figure, the first angle f and the second angle e can be approximately 10 to 40°. The first length d can be approximately 1 to 2.5 times the second length c. The second length c can be approximately 3 to 7 times the maximum axial displacement h of the thrust plate 105. In other embodiments, the angles f and e and the lengths d and c can be other suitable values ​​to implement the above functions.

[0037] Air gap 203 also includes a third air gap portion 206, which is configured to adjust the proportion of the electromagnetic field generated by coil 104 passing through the first air gap portion 204. The electromagnetic field generated by coil 104 passing through the third air gap portion 206 changes the proportion of the electromagnetic field passing through the first air gap portion 204. The first coupling portion 201 also includes a third inclined surface 211, and the second coupling portion 202 also includes a radially extending third radial surface 212. The third air gap portion 206 is formed between the third inclined surface 211 and the third radial surface 212. The third inclined surface 211 has a third length a along the axial direction and forms a third angle b relative to the axial direction. The third angle b is an acute angle. In other embodiments, the degree of inclination of the third inclined surface 211 relative to the axial direction can also be represented by an obtuse angle. The third length a and the third angle b are set to adjust the proportion of the electromagnetic field generated by coil 104 passing through the third air gap portion 206. The first air gap portion 204 is disposed close to the opening 106, and the third air gap portion 206 is disposed away from the opening 106. In the embodiment shown in the figure, the third angle b can be approximately 20 to 50°. In other embodiments, the third length a and the third angle b can be other suitable values ​​to implement the above-described function.

[0038] like Figure 2D As shown, the direction of the electromagnetic field generated by coil 104 through the first air gap portion 204 is inclined relative to the axial direction. The direction of the electromagnetic field generated by coil 104 through the second air gap portion 205 is approximately parallel to the axial direction, and the direction of the electromagnetic field generated by coil 104 through the third air gap portion 206 is curved. Figure 2B As shown, the housing 103 has two first coupling portions 201A and 201B symmetrically arranged relative to the opening 106. The thrust plate 105 has two second coupling portions 202A and 202B corresponding to the two first coupling portions 201A and 201B, respectively. Both the first coupling portions and the second coupling portions are annular. The first coupling portions 201A and 201B can be collectively referred to as the first coupling portion 201, and the second coupling portions 202A and 202B can be collectively referred to as the second coupling portion 202.

[0039] In the illustrated embodiment, the first air gap portion 204, the second air gap portion 205, and the third air gap portion 206 are sequentially adjacent. In other embodiments, the first air gap portion, the second air gap portion, and the third air gap portion include other adjacent orders (see...). Figures 5A-5F In other embodiments, the air gap between the first coupling portion and the second coupling portion may also include only the first air gap portion and the second air gap portion (see...). Figure 4 In other embodiments, the air gap between the first coupling portion and the second coupling portion may have other suitable shapes to implement the above-described functions.

[0040] Figure 3A A cross-sectional perspective view of a magnetic levitation bearing 300 according to another exemplary embodiment of this application is shown, which is consistent with... Figure 2A similar. Figure 3B It shows Figure 3A The partial cross-sectional view of the magnetic levitation bearing 300 shown is consistent with... Figure 2C similar. Figure 3C It shows Figure 3A A partial schematic diagram of the electromagnetic field generated by the coil in the magnetic levitation bearing 300, which is related to... Figure 2D similar.

[0041] Figures 3A-3C The magnetic levitation bearing 300 in the middle and Figure 2A-2D The magnetic bearing 100 is similar to that in the magnetic bearing 300. The difference is that the first coupling part 301 and the second coupling part 302 in the magnetic bearing 300 are respectively inverted relative to the first coupling part 201 and the second coupling part 202 in the magnetic bearing 100. Figures 3A-3CAs shown, the magnetic levitation bearing 300 includes a rotatable component 311, a fixed component 312, a housing 313, a coil 314, and a thrust plate 315. The housing 313 accommodates the coil 314 and includes an opening 316 facing the thrust plate 315. A first coupling portion 301 is provided on the housing 313, and a second coupling portion 302 is provided on the thrust plate 315. An air gap 303 is formed between the first coupling portion 301 and the second coupling portion 302. The air gap 303 includes a first air gap portion 304, a second air gap portion 305, and a third air gap portion 306. The first air gap portion 304 is disposed away from the opening 316, the third air gap portion 306 is disposed close to the opening 316, and the second air gap portion 305 is adjacent to the first air gap portion 304 and the third air gap portion 306. The first air gap portion 304, the second air gap portion 305, and the third air gap portion 306 are largely the same as the first air gap portion 204, the second air gap portion 205, and the third air gap portion 206, except for their different positions. The structure of the magnetic levitation bearing 300, which is the same as that of the magnetic levitation bearing 100, will not be described again here.

[0042] Figure 4 A partial cross-sectional view of a magnetic levitation bearing 400 according to another exemplary embodiment of this application is shown.

[0043] Figure 4 The magnetic levitation bearing 400 in Figure 2A-2D The magnetic levitation bearing 100 is similar. The difference is that, as Figure 4 As shown, in the magnetic levitation bearing 400, the housing 413 includes an opening 406 facing the thrust plate 415. A first coupling portion 401 is provided on the housing 413 adjacent to the opening 406, and a second coupling portion 402 is provided on the thrust plate 415. An air gap 403 is formed between the first coupling portion 401 and the second coupling portion 402, the air gap 403 including a first air gap portion 404 and a second air gap portion 405. The first air gap portion 404 and the second air gap portion 405 are respectively connected to the first air gap portion 204 and the second air gap portion 205 (see...). Figure 2C Similarly, the first air gap portion 404 is configured to reduce the change in electromagnetic force generated by the coil, for example, under a predetermined energizing current, within a predetermined axial position range of the thrust plate 415. The first air gap portion 404 is configured to provide a substantially uniform gap with respect to the axial direction. The second air gap portion 405 extends substantially radially. The first air gap portion 404 and the second air gap portion 405 cooperate such that, within the predetermined axial position range of the thrust plate 415, the change in electromagnetic force generated by the coil under a predetermined energizing current reaches a predetermined change value, and this electromagnetic force is substantially linearly related to the axial position of the thrust plate 415.

[0044] The first coupling portion 401 includes a first inclined surface 407 and a first radial surface 408 extending radially. The second coupling portion 402 includes a second inclined surface 409 and a second radial surface 410 extending radially. The first inclined surface 407 and the second inclined surface 409 are substantially parallel to form a first air gap portion 404, and the first radial surface 408 and the second radial surface 410 are substantially parallel to form a second air gap portion 405. The first inclined surface 407 forms a first angle f' relative to the axial direction, and the second inclined surface 409 forms a second angle e' relative to the axial direction. The first angle f' and the second angle e' are substantially the same and are configured to adjust the amount of variation in the gap provided by the first air gap portion 404 within a predetermined axial position range of the thrust plate 415. The first inclined surface 407 has a first length d' along the axial direction, and the second inclined surface 409 has a second length c' along the axial direction. The first length d' and the second length c' are configured to adjust the proportion of the electromagnetic field generated by the coil passing through the first air gap portion 404.

[0045] Figures 5A-5F Partial cross-sectional views of magnetic levitation bearings 500A-500F according to several exemplary embodiments of this application are shown. Figures 5A-5F The magnetic levitation bearings 500A-500F and Figure 2A-2D Similar to the magnetic levitation bearing 100. For example, in magnetic levitation bearings 500A-500F, an air gap is formed between a first coupling portion provided on the housing 504A-504F and a second coupling portion provided on the thrust plate 505A-505F. This air gap includes a first air gap portion 501A-501F, a second air gap portion 502A-502F, and a third air gap portion 503A-503F, which are similar to the first air gap portion 204, the second air gap portion 205, and the third air gap portion 206 of air gap 203, respectively. The difference is that the connection sequence and / or tilting direction of the first, second, and third air gap portions in magnetic levitation bearings 500A-500F are different from those of the first air gap portion 204, the second air gap portion 205, and the third air gap portion 206.

[0046] Figure 6 A schematic diagram showing the relationship between the electromagnetic force generated by the coil under a predetermined energizing current and the axial position of the thrust plate is shown.

[0047] like Figure 6 As shown, the horizontal axis represents the axial position of the thrust plate, and the vertical axis represents the electromagnetic force generated by the coil. The axial position of the thrust plate includes the position between position 1 (at the -0.6mm position) and position 2 (at the 0.6mm position). A position with a coordinate of zero represents the predetermined position of the thrust plate, such as the center position; a position with a negative coordinate represents the position where the thrust plate is away from the predetermined position from the coil; and a position with a positive coordinate represents the position where the thrust plate is closer to the coil from the predetermined position.

[0048] In the prior art, the air gap formed between the housing and the thrust plate extends radially. The solid lines show the relationship between the electromagnetic force generated by the coil and the axial position of the thrust plate under various predetermined energizing currents in the prior art. For the uppermost curve, within the four axial position ranges of the thrust plate (-0.6mm~0.4mm, 0.4mm~0mm, 0mm~0.2mm, and 0.2mm~0.6mm), the electromagnetic force generated by the coil and the axial position of the thrust plate are approximately linearly related. Under other currents, within three to five axial position ranges of the thrust plate, the electromagnetic force generated by the coil and the axial position of the thrust plate are approximately linearly related. Within the entire axial position range of the thrust plate (e.g., -0.6mm~0.6mm), the electromagnetic force generated by the coil and the axial position of the thrust plate are not linearly related, but rather exhibit a curve.

[0049] The dashed lines illustrate the relationship between the electromagnetic force generated by the coil and the axial position of the thrust plate in the magnetic levitation bearing of an exemplary embodiment of this application under predetermined energizing currents. Throughout the entire axial position range of the thrust plate (e.g., -0.6 mm to 0.6 mm), the electromagnetic force generated by the coil under each current exhibits a substantially linear relationship with the axial position of the thrust plate. In other words, compared to the prior art, the axial position range of the thrust plate corresponding to the substantially linear relationship between the electromagnetic force generated by the coil and the axial position of the thrust plate in this application is wider; that is, this application has a wider linear range.

[0050] Within the entire axial position range of the thrust plate (e.g., -0.6mm to 0.6mm), under the same current, the variation in electromagnetic force generated by the coil in this application (see dashed line) is less than the variation in electromagnetic force generated by the coil in the prior art (see solid line), resulting in a smoother change in electromagnetic force. Under the same current, at the same axial position of the thrust plate (e.g., axial position within the range of -0.6mm to 0.4mm), the electromagnetic force generated by the coil in this application is greater than the electromagnetic force generated by the coil in the prior art.

[0051] As previously stated, within the predetermined axial position range of the thrust plate, the electromagnetic force generated by the coil (which is approximately inversely proportional to the square of the axial position) changes smoothly and is linearly related to the axial position of the thrust plate. Correspondingly, the inductance of the coil (which is approximately inversely proportional to the axial position) changes even more smoothly and is linearly related to the axial position of the thrust plate. Compared to the prior art, the change in inductance of the coil in this application is smaller (more smooth) within the entire axial position range of the thrust plate (e.g., -0.6mm to 0.6mm), thus the inductance of the coil is more approximately linearly related to the axial position of the thrust plate. However, the smooth change in inductance may result in the same inductance corresponding to multiple approximately identical axial positions of the thrust plate, which is not conducive to accurately obtaining the axial position of the thrust plate. Therefore, within the axial position range of the thrust plate (e.g., -0.6mm to 0.6mm), the straight line (see dashed line) formed by the electromagnetic force generated by the coil and the axial position of the thrust plate is not completely horizontal, but retains a certain tilt angle. The above configuration allows the rate of change of the inductance generated by the coil relative to the axial position of the thrust plate to reach a predetermined rate of change within the axial position range of the thrust plate, thereby enabling a more accurate determination of the corresponding axial position of the thrust plate based on the inductance. For example, the rate of change (the slope of the corresponding straight line) of the electromagnetic force generated by the coil relative to the axial position of the thrust plate can be changed by altering the proportion of the electromagnetic field generated by the coil through the first air gap portion and / or the proportion of the electromagnetic field generated by the coil through the third air gap portion, thereby obtaining the desired correlation between the inductance generated by the coil and the axial position of the thrust plate (for example, see...). Figure 7 Within the axial position range of the thrust plate, the variation in the electromagnetic force generated by the coil under multiple predetermined energizing currents can be adjusted so that the inductance of the coil under multiple predetermined energizing currents has approximately the same linear relationship with the axial position of the thrust plate.

[0052] Figure 7 A schematic diagram showing the relationship between the inductance of the coil and the axial position of the thrust plate under a predetermined energizing current is shown.

[0053] like Figure 7As shown, the horizontal axis represents the axial position of the thrust plate, and the vertical axis represents the inductance of the coil. The solid line represents the relationship between the coil inductance and the axial position of the thrust plate at the maximum predetermined current. The dashed line represents the relationship between the coil inductance and the axial position of the thrust plate at the minimum predetermined current. As shown, the coil inductance and the axial position of the thrust plate are approximately linearly related at both the maximum and minimum predetermined currents. Furthermore, the fact that the solid and dashed lines approximately coincide indicates that the above linear relationship is approximately the same. In this application, the coil inductance and the axial position of the thrust plate are also linearly related (not shown) at various other predetermined currents between the maximum and minimum predetermined currents, and are approximately the same as the linear relationships described above at the maximum and minimum predetermined currents.

[0054] Figure 8 A structural block diagram of a control system 800 for controlling a magnetic levitation bearing according to an exemplary embodiment of this application is shown.

[0055] like Figure 8 As shown, the control system 800 includes a rectifier unit 801, a drive unit 802, a data acquisition device, and a control device 808. The rectifier unit 801 is configured to generate a bus voltage. The drive unit 802 is configured to receive the bus voltage and generate current to drive the coil 803 of the magnetic levitation bearing. The coil 803 of the magnetic levitation bearing is energized by the drive unit 802 to generate electromagnetic force to move the thrust plate of the magnetic levitation bearing toward the coil. The coil 803 includes the coil in the magnetic levitation bearing of this application. The data acquisition device includes a voltage sampling unit 804 and a current sampling unit 806. The voltage sampling unit 804 is configured to sample the bus voltage received by the drive unit 802 to obtain a sampled bus voltage. The current sampling unit 806 is configured to sample the current applied to the coil 803 to obtain a sampled coil current. The control device 808 is configured to control the operation of the drive unit 802, thereby controlling the movement of the thrust plate. The control device 808 can control the operation of the drive unit 802 based on the sampled bus voltage and coil current. For example, it can control the current applied to the coil 803 by the drive unit 802, thereby controlling the axial movement of the thrust plate.

[0056] The control system 800 also includes a voltage filtering unit 805 and a current filtering unit 807. The voltage filtering unit 805 is configured to perform a low-pass filter on the sampled bus voltage to obtain the low-frequency component of the bus voltage, i.e., to filter out interference. The current filtering unit 807 is configured to perform a high-pass filter on the sampled coil current to obtain the high-frequency component of the coil current. In one embodiment, when the control coil is energized, a high-frequency alternating pulse width signal with an alternating frequency of f and a duty cycle of Duty is doped into the fundamental current that plays a control role. The high-frequency component I of the coil current is: , Where Duty represents the duty cycle, Vdc represents the low-frequency component of the bus voltage, Z represents the coil impedance, R represents the coil resistance, and X... L Let L represent the inductive reactance of the coil, L represent the inductance of the coil, and f represent the alternating frequency. When the alternating frequency f is high frequency, for example, making Then the inductive reactance X of the coil L The dominant factor is the impedance Z of the coil. At this point, X... L ≈ (Duty) Therefore, the inductive reactance X of the coil can be obtained based on the low-frequency component Vdc of the bus voltage and the high-frequency component I of the coil current. L In this embodiment, the voltage filtering unit 805 and the current filtering unit 807 are hardware circuits. In other embodiments, the voltage filtering unit 805 and the current filtering unit 807 can implement the above functions through software modules.

[0057] The control device 808 includes an inductive reactance acquisition unit 809, an inductance acquisition unit 810, a position acquisition unit 811, a position control unit 812, a fundamental signal generation circuit 813, an alternating signal generation circuit 814, and a drive signal generation circuit 815. The inductive reactance acquisition unit 809 is configured to acquire the inductive reactance X of the coil based on the low-frequency component of the bus voltage and the high-frequency component of the coil current. L For example, as mentioned earlier, X L ≈ (Duty) Vdc) / I. In other embodiments, the inductive reactance X of the coil can be obtained in other ways. L The inductance acquisition unit 810 is configured based on the inductive reactance X of the coil. L To obtain the inductance of the coil. For example, L=X L / (2πf), where L represents the inductance of the coil, X LLet f represent the inductive reactance of the coil, and f represent the aforementioned alternating frequency. The position acquisition unit 811 is configured to acquire the current axial position of the thrust plate based on the inductance of the coil. As previously described, in the magnetic levitation bearing of this application, the inductance of the coil is linearly related to the axial position of the thrust plate. Therefore, by acquiring this linear relationship, the current axial position of the thrust plate can be acquired based on the inductance of the coil. The position control unit 812 is configured to generate a position control signal based on the current axial position of the thrust plate and the target position of the thrust plate. For example, the position control unit 812 is a PID controller. In other embodiments, the position control unit 812 includes other suitable means to implement the above functions. In one embodiment, the inductive reactance acquisition unit 809, the inductance acquisition unit 810, the position acquisition unit 811, and the position control unit 812 may be implemented by a processor in the control device 808. In other embodiments, these units may be implemented by other suitable means.

[0058] The fundamental signal generation circuit 813 is configured to generate a fundamental signal based on a position control signal. The alternating signal generation circuit 814 is configured to generate an alternating signal. The drive signal generation circuit 815 is configured to generate a control signal for the drive unit 802 based on the received fundamental signal and the alternating signal. In other embodiments, the control system 800 includes other suitable structures to implement the above functions.

[0059] Figure 9 A flowchart illustrating a control method 900 for controlling a magnetic levitation bearing according to an exemplary embodiment of this application is shown. As previously described, in the magnetic levitation bearing of this application, the inductance of the coil under multiple predetermined energizing currents has a substantially linear relationship with the axial position of the thrust plate. Therefore, this application can obtain the axial position of the thrust plate based on the inductance of the coil without using a sensor to detect the axial position of the thrust plate.

[0060] like Figure 9 As shown, the control method 900 for controlling a magnetic levitation bearing includes steps 902, 904, and 906. In step 902, the inductance of the magnetic levitation bearing coil is obtained, and then the process proceeds to step 904. In step 904, the current axial position of the thrust plate is obtained based on the correlation between the coil inductance and the axial position of the thrust plate of the magnetic levitation bearing, using the obtained inductance, and then the process proceeds to step 906. In step 906, the drive unit 802 (see [reference needed]) is controlled based on the obtained current axial position of the thrust plate. Figure 8 The coil is energized to control the movement of the thrust plate. In other embodiments, the control method includes other suitable steps to control the operation of the magnetic levitation bearing.

[0061] Figure 10 It shows Figure 9 The detailed flowchart of step 902 is shown.

[0062] like Figure 10 As shown, Figure 9 The illustrated step 902 for obtaining the inductance of the coil includes steps 1002-1008. At step 1002, the bus voltage received by the drive unit 802 is sampled to obtain a sampled bus voltage, and then the process proceeds to step 1004. At step 1004, the coil current is sampled to obtain a sampled coil current, and then the process proceeds to step 1006. At step 1006, the inductive reactance of the coil is obtained based on the sampled bus voltage and coil current, and then the process proceeds to step 1008. In one embodiment, obtaining the inductive reactance of the coil includes: low-pass filtering the sampled bus voltage to obtain a low-frequency component of the bus voltage; high-pass filtering the sampled coil current to obtain a high-frequency component of the coil current; and obtaining the inductive reactance of the coil based on the low-frequency component of the bus voltage and the high-frequency component of the coil current. For example, using the above formula X... L ≈ (Duty) The inductive reactance of the coil is obtained by taking Vdc / I. In other embodiments, the inductive reactance of the coil can be obtained by other suitable methods. At step 1008, the inductance of the coil is obtained based on the inductive reactance of the coil. For example, using the above formula L=X L / (2πf) is used to obtain the inductance of the coil.

[0063] Figure 11 It shows according to Figure 8 The software structure block diagram of the control device 808 shown is shown.

[0064] like Figure 11 As shown, the control device 808 includes a processor 1102, a memory 1103, an input interface 1104, an output interface 1105, and a bus 1101. The processor 1102, memory 1103, input interface 1104, and output interface 1105 are connected to the bus 1101. The processor 1102 can read a program (or instruction) from the memory 1103 and execute the program (or instruction) to perform data processing. The processor 1102 can also write data or a program (or instruction) into the memory 1103. The memory 1103 can store programs (instructions) or data. By executing the instructions in the memory 1103, the processor 1102 can control the memory 1103, the input interface 1104, and the output interface 1105.

[0065] In one embodiment, input interface 1104 is configured to receive sampled bus voltage from voltage sampling unit 804 and sampled coil current from current sampling unit 806 (see...). Figure 8 The input interface 1104 is also configured to convert the received data of these parameters into data that the processor 1102 can recognize, and output this data to the processor 1102.

[0066] Processor 1102 is configured to process (e.g., calculate) the received data to generate a position control signal for controlling the axial movement of the thrust disc. In one embodiment, processor 1102 is configured to execute Figure 9-10 The control method described in the text is as follows: Processor 1102 obtains the inductive reactance of the coil based on sampled bus voltage and coil current, obtains the inductance of the coil based on the inductive reactance, and obtains the current axial position of the thrust plate of the magnetic levitation bearing based on the inductance and the correlation between the inductance of the coil and the axial position of the thrust plate of the magnetic levitation bearing (e.g., stored in memory 1103 and retrieved by processor 1102 from memory 1103). Processor 1102 also generates a position control signal based on the current axial position of the thrust plate and a target position (e.g., a preset target axial position). Output interface 1105 is configured to receive the position control signal from processor 1102, convert the signal into a signal suitable for fundamental signal generation circuit 813 for output to fundamental signal generation circuit 813 (see...). Figure 8 ).

[0067] The hardware structure of the control device 808 includes a fundamental signal generation circuit 813, an alternating signal generation circuit 814, and a drive signal generation circuit 815 (see...). Figure 8 The fundamental signal generating circuit 813 generates a corresponding fundamental signal based on the position control signal, and the alternating signal generating circuit 814 generates an alternating signal. The drive signal generating circuit 815 generates a control signal for the drive unit 802 based on the fundamental signal and the alternating signal, so that the drive unit 802 applies a corresponding current to the coil, thereby controlling the thrust plate to move to the target position.

[0068] Although this application has been described with reference to examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and / or substantially equivalents, whether known or currently or soon to be foreseen, will likely be apparent to those skilled in the art. Furthermore, the technical effects and / or technical problems described herein are exemplary and not limiting; therefore, the disclosures herein may be used to solve other technical problems and have other technical effects and / or can solve other technical problems. Thus, the examples of embodiments of this application as set forth above are intended to be illustrative and not limiting. Various changes can be made without departing from the spirit or scope of this application. Therefore, this application is intended to include all known or previously developed alternatives, modifications, variations, improvements, and / or substantially equivalents.

Claims

1. A magnetic levitation bearing for magnetically connecting a rotatable component (101) relative to a fixed component (102), characterized in that, The magnetic levitation bearing (100) includes: A thrust plate (105) is fixed to a rotatable component (101) and extends radially relative to the rotatable component (101); A coil (104), axially spaced from the thrust plate (105), is configured to generate an electromagnetic force when energized, causing the thrust plate (105) to move axially toward the coil (104); and A housing (103) is fixed to a fixing member (102), the housing (103) houses the coil (104) and includes an opening (106) facing the thrust plate (105). The housing (103) is provided with a first coupling portion (201) adjacent to the opening (106), and the thrust plate (105) is provided with a second coupling portion (202). An air gap (203) is formed between the first coupling part (201) and the second coupling part (202). The air gap (203) includes a first air gap portion (204), which is configured to reduce the amount of change in the electromagnetic force generated by the coil (104) within a predetermined axial position range of the thrust plate (105).

2. The magnetic levitation bearing according to claim 1, characterized in that, The first air gap portion (204) is configured to provide a generally uniform gap that is inclined relative to the axial direction.

3. The magnetic levitation bearing according to claim 2, characterized in that, The air gap (203) also includes a second air gap portion (205) that extends substantially radially. The first air gap portion (204) and the second air gap portion (205) cooperate to ensure that, within a predetermined axial position range of the thrust plate (105), the change in the electromagnetic force generated by the coil (104) under a predetermined energizing current reaches a predetermined change value, and the electromagnetic force is approximately linearly related to the axial position of the thrust plate (105).

4. The magnetic levitation bearing according to claim 3, characterized in that, The first coupling portion (201) includes a first inclined surface (207) and a first radial surface (208) extending radially, and The second coupling portion (202) includes a second inclined surface (209) and a second radial surface (210) extending radially. The first inclined surface (207) is substantially parallel to the second inclined surface (209) to form the first air gap portion (204), and the first radial surface (208) and the second radial surface (210) are substantially parallel to form the second air gap portion (205).

5. The magnetic levitation bearing according to claim 4, characterized in that, The first inclined surface (207) forms a first angle f with respect to the axial direction, and the second inclined surface (209) forms a second angle e with respect to the axial direction. The first angle f is approximately the same as the second angle e and is set to adjust the amount of change in the gap provided by the first air gap portion (204) within a predetermined axial position range of the thrust plate (105).

6. The magnetic levitation bearing according to claim 5, characterized in that, The first inclined surface (207) has a first length d along the axial direction, and the second inclined surface (209) has a second length c along the axial direction. Wherein, the first length d and the second length c are set to adjust the proportion of the electromagnetic field generated by the coil (104) through the first air gap portion (204).

7. The magnetic levitation bearing according to claim 3, characterized in that, The air gap (203) further includes a third air gap portion (206), which is configured to adjust the proportion of the electromagnetic field generated by the coil (104) passing through the first air gap portion (204).

8. The magnetic levitation bearing according to claim 7, characterized in that, The first coupling portion (201) further includes a third inclined surface (211); and The second coupling portion (202) also includes a third radial surface (212) extending radially. The third air gap portion (206) is formed between the third inclined surface (211) and the third radial surface (212), and The third inclined surface (211) has a third length a along the axial direction and a third angle b relative to the axial direction. The third length a and the third angle b are set to adjust the proportion of the electromagnetic field generated by the coil (104) through the third air gap portion (206).

9. The magnetic levitation bearing according to claim 1, characterized in that, The plurality of axial positions include a plurality of axial positions away from the coil (104).

10. The magnetic levitation bearing according to claim 3, characterized in that, Within a predetermined axial position range of the thrust plate (105), the variation in the electromagnetic force generated by the coil (104) under a plurality of predetermined energizing currents can be adjusted so that the inductance of the coil (104) under the plurality of predetermined energizing currents has approximately the same linear relationship as the axial position of the thrust plate (105).

11. The magnetic levitation bearing according to claim 1, characterized in that, The housing (103) is provided with two first coupling portions (201A, 201B) symmetrically arranged relative to the opening (106), and The thrust plate (105) is provided with two second coupling parts (202A, 202B) corresponding to the two first coupling parts (201A, 201B).

12. The magnetic levitation bearing according to claim 1, characterized in that, The coil (104) is annular, and the housing (103) has an annular groove for accommodating the coil (104).

13. A control method for controlling a magnetic levitation bearing (100) according to any one of claims 1-12, wherein the coil (104) of the magnetic levitation bearing is energized by a drive unit (802), characterized in that, The control method (900) includes: Obtain the inductance of the coil (104) of the magnetic levitation bearing; The current axial position of the thrust plate (105) is obtained by means of the acquired inductance, based on the correlation between the inductance of the coil (104) and the axial position of the thrust plate (105) of the magnetic levitation bearing; and The drive unit (802) is controlled to energize the coil (104) based on the current axial position of the thrust plate (105), thereby controlling the movement of the thrust plate (105).

14. The control method according to claim 13, characterized in that, The association includes: The inductance of the coil (104) under a plurality of predetermined energizing currents is approximately linearly related to the axial position of the thrust plate (105).

15. The control method according to claim 13, characterized in that, Obtaining the inductance of the coil (104) includes: The bus voltage received by the drive unit (802) is sampled to obtain the sampled bus voltage; The current of the coil (104) is sampled to obtain the sampled coil current; The inductive reactance of the coil (104) is obtained based on the sampled bus voltage and coil current; and The inductance of the coil (104) is obtained based on the inductive reactance of the coil (104).

16. The control method according to claim 15, characterized in that, Obtaining the inductive reactance of the coil (104) includes: The sampled bus voltage is low-pass filtered to obtain the low-frequency component of the bus voltage. The sampled coil current is high-pass filtered to obtain the high-frequency component of the coil current; and The inductive reactance of the coil (104) is obtained based on the low-frequency component of the bus voltage and the high-frequency component of the coil current.

17. A control system for controlling a magnetic levitation bearing (100), characterized in that, The control system (800) includes: A control device (808) is configured to perform the control method according to any one of claims 13-16 to control the movement of the thrust plate (105) of the magnetic levitation bearing (100).

18. The control system according to claim 17, characterized in that, The control system (800) further includes: A rectifier unit (801) is configured to generate a bus voltage; A drive unit (802) configured to receive the bus voltage and drive the coil (104) of the magnetic levitation bearing (100); and Acquisition devices (804, 806) are configured to sample the bus voltage received by the drive unit (802) to obtain a sampled bus voltage, and to sample the current of the coil (104) to obtain a sampled coil current. The control device (808) is configured to perform the control method based on the sampled bus voltage and coil current.

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