Methods and tools for defining the protective boundaries of suspended magnetic and centrifugal compressors.

Abstract

Invention details;

Description

Method and device for determining magnetic levitation protection boundary, and centrifugal compressor

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application No. 202310853500.9, filed on July 12, 2023, entitled “Method for determining magnetic levitation protection boundary, device therefor, and centrifugal compressor,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the technical field of magnetic levitation centrifugal compressors, and in particular to a method for determining a magnetic levitation protection boundary, a device thereof, and a centrifugal compressor. Background Art

[0004] Magnetic levitation centrifugal compressors are widely used in air conditioning systems due to their low noise, low maintenance costs, high efficiency, lightweight design, and low starting current. A magnetic levitation centrifugal compressor consists of a magnetic levitation rotor, stator, magnetic bearings, position sensors, protective bearings, and a bearing controller. The bearing controller ensures stable levitation of the magnetic levitation rotor. Precise levitation control is crucial for the proper operation of a magnetic levitation centrifugal compressor.

[0005] Public content

[0006] In view of this, the present disclosure aims to solve at least one of the problems in the related art to a certain extent. To this end, the present disclosure aims to provide a method and device for determining a magnetic levitation protection boundary, and a centrifugal compressor.

[0007] The present disclosure provides a method for determining a magnetic levitation protection boundary, which is used for a magnetic levitation centrifugal compressor. The magnetic levitation centrifugal compressor includes: a magnetic levitation rotor, a protection bearing, a radial bearing and a distance sensor, and the distance sensor is used to measure the distance between the suspension center of the magnetic levitation rotor and the distance sensor. The determination method includes: obtaining a mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing; determining the boundary distance of the suspension center relative to the distance sensor in multiple directions when the suspension position of the magnetic levitation rotor changes in multiple directions according to the mapping relationship, and determining the protection bearing boundary points of the suspension center in multiple directions inside the protection bearing according to the boundary distance; and forming the protection boundary according to the protection bearing boundary points.

[0008] The present disclosure also provides a device for determining a magnetic levitation protection boundary, which is used for a magnetic levitation centrifugal compressor. The magnetic levitation centrifugal compressor includes: a magnetic levitation rotor, a protection bearing, a radial bearing and a distance sensor, and the distance sensor is used to measure the distance between the suspension center of the magnetic levitation rotor and the distance sensor. The determination device includes an acquisition module, a first determination module and a second determination module. The acquisition module is used to obtain the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing; the first determination module is used to determine the boundary distance of the suspension center relative to the distance sensor in multiple directions when the suspension position of the magnetic levitation rotor changes in multiple directions according to the mapping relationship, and determine the protection bearing boundary points of the suspension center in multiple directions inside the protection bearing according to the boundary distance; the second determination module is used to form the protection boundary according to the protection bearing boundary points.

[0009] The present disclosure also provides a control method for controlling a magnetically suspended rotor of a magnetically suspended centrifugal compressor. The magnetically suspended centrifugal compressor includes the determination device described in the above embodiment, and the control method includes: controlling the suspension center of the magnetically suspended rotor to adjust within the protection boundary range.

[0010] The present disclosure also provides a control device for controlling a magnetically suspended rotor of a magnetically suspended centrifugal compressor. The magnetically suspended centrifugal compressor includes the determination device described in the above embodiment, and the control device is used to control the suspension center of the magnetically suspended rotor to adjust within the protection boundary.

[0011] The present disclosure further provides a magnetic levitation centrifugal compressor, which includes the determination device described in the above embodiment and the control device described in the above embodiment.

[0012] The present disclosure also provides an air conditioning unit, which includes the magnetic levitation centrifugal compressor described in the above embodiment.

[0013] The present disclosure also provides a non-volatile computer-readable storage medium containing a computer program. When the computer program is executed by one or more processors, the determination method or control method described in any one of the above embodiments is implemented.

[0014] The method and device for determining the magnetic levitation protection boundary and the centrifugal compressor disclosed in the present invention can accurately determine the magnetic levitation protection boundary corresponding to the protection bearing when the suspension position of the magnetic levitation rotor is adjusted, thereby determining the actual activity space of the magnetic levitation rotor after removing the clearance of the protection bearing, thereby ensuring the normal operation of the compressor.

[0015] Additional aspects and advantages of the present disclosure will be given in part in the description that follows and, in part, will be obvious from the description that follows, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0017] FIG1 is a schematic structural diagram of a magnetic levitation centrifugal compressor in the related art;

[0018] FIG2 is a schematic diagram of a scenario in which a magnetic levitation centrifugal compressor in the related art uses a bearing current to find a protection boundary of a front protection bearing;

[0019] FIG3 is a schematic diagram of a scenario in which a magnetic levitation centrifugal compressor in the related art uses a bearing current to find a protection boundary of a rear protection bearing;

[0020] FIG4 is a schematic diagram of a scenario in which a magnetic levitation centrifugal compressor in the related art uses a bearing current to find the axial boundary of an axial protection bearing;

[0021] FIG5 is a schematic diagram of a structure of a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure;

[0022] FIG6 is a second structural schematic diagram of a magnetic levitation centrifugal compressor according to certain embodiments of the present disclosure;

[0023] FIG7 is a flowchart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0024] FIG8 is a schematic diagram of a structure of a device for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0025] FIG9 is a schematic diagram of a curve of a first radial mapping relationship in a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0026] FIG10 is a schematic diagram of a scenario in which a front protective bearing of a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure is radially partitioned;

[0027] FIG11 is a second structural schematic diagram of a device for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0028] FIG12 is a second flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0029] FIG13 is a schematic diagram of a curve of a first radial mapping relationship in a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0030] FIG14 is a third flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0031] FIG15 is a fourth flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0032] FIG16 is a schematic diagram of a scenario in which a magnetic levitation rotor of a magnetic levitation centrifugal compressor according to certain embodiments of the present disclosure is divided into rotation directions;

[0033] FIG17 is a schematic diagram of a curve of a first axial mapping relationship, a second axial mapping relationship, or a third axial mapping relationship in a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0034] FIG18 is a fifth flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0035] FIG19 is a sixth flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0036] FIG20 is a schematic diagram of a scenario in which a rear protection bearing of a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure is radially partitioned;

[0037] FIG21 is a schematic diagram of a curve of a second radial mapping relationship in a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0038] FIG22 is a seventh flow chart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0039] FIG23 is a flowchart of an eighth method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0040] FIG24 is a ninth flowchart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0041] FIG25 is a schematic diagram of a scenario showing a protection boundary of a front protection bearing determined by a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure;

[0042] FIG26 is a schematic diagram of a scenario showing a protection boundary of a rear protection bearing determined by a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure;

[0043] FIG27 is a tenth flowchart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0044] FIG28 is a flowchart of the eleventh method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0045] FIG29 is a twelfth flowchart of a method for determining a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0046] FIG30 is a schematic diagram of a scenario showing an axial boundary determined by a magnetically suspended centrifugal compressor according to certain embodiments of the present disclosure;

[0047] FIG31 is a schematic diagram of the structure of a control device for a magnetic levitation protection boundary according to certain embodiments of the present disclosure;

[0048] FIG32 is a third schematic diagram of the structure of a magnetically levitated centrifugal compressor according to certain embodiments of the present disclosure. DETAILED DESCRIPTION

[0049] The embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and are not to be construed as limiting the present disclosure.

[0050] In the description of the present disclosure, features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, "plurality" means two or more, unless otherwise explicitly or specifically defined.

[0051] The present disclosure may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0052] The embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and are not to be construed as limiting the present disclosure.

[0053] At present, for the suspension position of the magnetic levitation rotor, the industry mostly uses the center position of the protective bearing as the center of the circle and the radius of the protective bearing to set the suspension boundary of the magnetic levitation rotor. The detection error caused by the clearance of the protective bearing when finding the boundary is ignored, resulting in inaccurate boundary determination. The magnetic levitation rotor suspension based on this boundary cannot play the role of protecting the magnetic levitation protective bearing, and in severe cases will cause damage to the magnetic levitation centrifugal compressor.

[0054] As can be understood, referring to Figure 1, the magnetic levitation centrifugal compressor includes a magnetic levitation protection bearing and a rotor P. The magnetic levitation protection bearing includes a front protection bearing Q1, a rear protection bearing Q2, an axial protection bearing Q3, and an axial protection bearing Q4. Both the front protection bearing Q1 and the rear protection bearing Q2 adjust the levitation center of the magnetic levitation rotor to move radially. The axial protection bearings Q3 and Q4 adjust the levitation center of the magnetic levitation rotor to move axially.

[0055] Please refer to Figures 2, 3, and 4. Figure 2 is a schematic diagram of boundary search based on the center position of the front protective bearing in the related art. Figure 3 is a schematic diagram of boundary search based on the center position of the rear protective bearing in the related art. Figure 4 is a schematic diagram of boundary search based on the center position of the axial protective bearing in the related art. Figure 2 shows the forward boundary of the magnetically levitated rotor suspension, obtained by applying a current to the front protective bearing, with the center position of the front protective bearing of a magnetically levitated centrifugal compressor as the center. Figure 3 shows the backward boundary of the magnetically levitated rotor suspension, obtained by applying a current to the rear protective bearing, with the center position of the rear protective bearing of a magnetically levitated centrifugal compressor as the center. Figure 4 shows the axial boundary of the magnetically levitated rotor suspension, obtained by applying a current to the protective bearing. In Figure 4, AZ1 represents the first axial end direction of the magnetically levitated rotor, and AZ2 represents the second axial end direction of the magnetically levitated rotor. As can be seen from Figures 2, 3, and 4, setting the protection boundary of the magnetically levitated rotor suspension based on the center position of the protective bearing and the radius of the protective bearing ignores the detection error caused by the clearance of the protective bearing when searching for the boundary, resulting in inaccurate boundary determination. Among them, the clearance of the protective bearing includes the gap between the inner wall of the front protective bearing and the maximum calibration boundary of the front protective bearing in Figure 2, the gap between the inner wall of the rear protective bearing and the maximum calibration boundary of the rear protective bearing in Figure 3, and the gap between the inner wall of the axial protective bearing and the maximum calibration boundary of the axial protective bearing in Figure 4.

[0056] In view of this, referring to Figures 5, 6, and 7, the present disclosure provides a method for determining a magnetic levitation protection boundary for a magnetic levitation centrifugal compressor 100. The magnetic levitation centrifugal compressor 100 includes a magnetic levitation rotor 110, a protection bearing 120, a radial bearing 130, and a distance sensor 140. The distance sensor 140 is used to measure the distance between the levitation center O of the magnetic levitation rotor 110 and the distance sensor 140. The determination method includes:

[0057] 02: Obtain the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing;

[0058] 04: Determine the boundary distances of the suspension center relative to the distance sensor in multiple directions when the magnetic suspension rotor changes its suspension position in multiple directions based on the mapping relationship, and determine the protective bearing boundary points of the suspension center in multiple directions inside the protective bearing based on the boundary distances;

[0059] 06: Form a protection boundary based on the protection bearing boundary points.

[0060] 8 , the present disclosure further provides a device 10 for determining a magnetic levitation protection boundary, which is used in a magnetic levitation centrifugal compressor 100 . The device 10 includes an acquisition module 12 , a first determination module 14 , and a second determination module 16 .

[0061] Step 02 may be implemented by the acquisition module 12 , step 04 may be implemented by the first determination module 14 , and step 06 may be implemented by the second determination module 16 .

[0062] That is, the acquisition module 12 is used to obtain the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing; the first determination module 14 is used to determine the boundary distances of the suspension center relative to the distance sensor in multiple directions when the suspension position of the magnetic levitation rotor changes in multiple directions based on the mapping relationship, and determine the protective bearing boundary points of the suspension center in multiple directions inside the protective bearing based on the boundary distances; the second determination module 16 is used to form a protection boundary based on the protective bearing boundary points.

[0063] Please refer to Figure 5 or Figure 6. In one embodiment, the bearing centerline of the radial bearing 130 coincides with the bearing centerline of the protective bearing 120, the radial bearing 130 is separated from the protective bearing 120 by a predetermined distance, and the distance sensor 140 is disposed on the radial bearing 130 and / or at the end of the magnetic levitation rotor 110.

[0064] Among them, the distance sensor 140 is set on the radial bearing 130 and / or the end of the magnetic levitation rotor 110, which includes three situations: first, the distance sensor 140 is only provided on the radial bearing 130 of the magnetic levitation centrifugal compressor 100, so that the protection boundaries corresponding to the protection bearing 120 in different radial directions can be obtained; second, the distance sensor 140 is only provided at the end of the magnetic levitation rotor 110 of the magnetic levitation centrifugal compressor 100, so that the protection boundaries corresponding to the protection bearing 120 in different axial directions can be obtained; third, the distance sensor 140 is provided on the radial bearing 130 of the magnetic levitation centrifugal compressor 100 and the end of the magnetic levitation rotor 110 of the magnetic levitation centrifugal compressor 100, so that the protection boundaries corresponding to the protection bearing 120 in different radial and axial directions can be obtained.

[0065] It is understood that the radial bearing 130 in the magnetic levitation centrifugal compressor 100 is composed of coils, the bearing centerlines of the protective bearing 120 and the radial bearing 130 coincide, and the radial bearing 130 and the protective bearing 120 are separated by a predetermined distance, which can be, for example, 5 cm, 5.5 cm, 6 cm, or other values, without limitation herein. That is, the distance between the radial bearing 130 and the protective bearing 120 is relatively close. When the magnetic levitation rotor 110 approaches the radial bearing 130, the current generated by the coil of the radial bearing 130 varies depending on the distance between the levitation center and the distance sensor. In other words, the installation position of the distance sensor 140 and the position of the coil of the radial bearing 130 are in a one-to-one correspondence. Therefore, the present disclosure allows the installation of the distance sensor 140 on the radial bearing 130 or at the end of the magnetic levitation rotor 110, thereby pre-determining the mapping relationship between the distance between the levitation center of the magnetic levitation rotor 110 and the distance sensor 140 and the coil current of the radial bearing 130.

[0066] For example, the mapping relationship between the distance between the suspension center of the magnetic levitation rotor and the distance sensor and the coil current of the front radial bearing is shown in the curve relationship of Figure 9. The horizontal axis in Figure 9 represents the distance d between the suspension center of the magnetic levitation rotor and the distance sensor installed on the outer wall of the front protective bearing during the radial movement along L1 in Figure 10, and the vertical axis represents the coil current i of the front radial bearing. Curve S1 can represent the mapping relationship between the distance d between the suspension center of the magnetic levitation rotor and the distance sensor and the corresponding coil current i of the radial bearing.

[0067] To mount the distance sensor 140 on the radial bearing 130, the radial bearing 130 is provided with a bearing bracket and an annular fixing member. The annular fixing member is connected to the bearing bracket, and the distance sensor 140 is mounted on the annular fixing member. In other words, the distance sensor 140 of the present disclosure can be mounted directly on the radial bearing 130 or indirectly fixed to the radial bearing 130 via the annular fixing member. The annular fixing member can be an aluminum ring or a ring made of other materials, without limitation.

[0068] In some embodiments, the radius of the radial bearing 130 or the annular fixing member is greater than or equal to the radius of the protective bearing 120. This ensures that the distance sensor 140 on the annular fixing member can detect the distance between the suspension center of the magnetic levitation rotor 110 and the distance sensor 140 in real time. Furthermore, the magnetic levitation protection boundary corresponding to the protective bearing 120 can be determined through the mapping relationship between the distance detected by the distance sensor 140 set on the radial bearing 130 and the coil current of the protective bearing 120.

[0069] After obtaining the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the protective bearing, the boundary distances of the suspension center relative to the distance sensor in multiple directions when the magnetic levitation rotor changes its suspension position in multiple directions are determined based on the mapping relationship, and the protective bearing boundary points of the suspension center in multiple directions inside the protective bearing are determined based on the boundary distances.

[0070] Specifically, as shown in Figure 9, curve A0(d0, i0) in curve S1 indicates that when the suspension center is at the center of the forward bearing, the distance between the distance sensor and the suspension center is d0, and the coil current of the forward bearing at this time is i0. In other words, the suspension center at this time can correspond to point B0(x0, y0) in the two-dimensional bearing coordinate system of Figure 10. In other words, the distance sensor corresponding to the change in suspension position at this time can be taken as the center of the forward bearing.

[0071] The curve in Figure 9 shows inflection points A1(d1, i1) and A2(d2, i2), where d1 and d2 are the distances between the distance sensor and the center of levitation, i1 is the coil current of the front radial bearing when the distance between the distance sensor and the center of levitation is d1, and i2 is the coil current of the front radial bearing when the distance between the distance sensor and the center of levitation is d2. In conjunction with Figure 10, the inflection points A1(d1, i1) and A2(d2, i2) in Figure 9 correspond to points B1(x1, y1) and B2(x2, y2) in the two-dimensional bearing coordinate system of Figure 10, respectively.

[0072] Therefore, at this time, d1 and d2 in the inflection points A1 (d1, i1) and A2 (d2, i2) are the boundary distances. At this time, the radial front protective bearing boundary points of L1 in Figure 10 can be correspondingly determined as points B1 (x1, y1) and B2 (x2, y2).

[0073] By analogy, we can obtain the radial front protection bearing boundary points of L2, L3, and L4 in Figure 10, which correspond to B3 (x3, y3), B4 (x4, y4), B5 (x5, y5), B6 ​​(x6, y6), B7 (x7, y7), and B8 (x8, y8) in Figure 10. In this way, a protection boundary can be formed based on these front protection bearing boundary points.

[0074] Referring to Figures 5, 6, and 10, distance sensors 3 and 1 may be provided at opposite ends of the outer wall of the front radial bearing 131. Distance sensor 1 is provided on the outer wall of one end of the radial direction L1 of the front radial bearing 131, and distance sensor 3 is provided on the outer wall of the other end of the radial direction L1 of the front radial bearing 131. In other words, the present disclosure can determine the distance between the rotor's suspension center and the distance sensors using distance sensor 3 and distance sensor 1. The distance between the rotor's suspension center and the distance sensors can be determined by the voltage difference between the feedback from distance sensor 3 and distance sensor 1.

[0075] It can be understood that when the rotor approaches the distance sensor 3, the distance sensor 3 gives the rotor a very strong high-frequency excitation force, thereby generating an eddy current on the rotor. The closer the rotor is to the distance sensor 3, the stronger the eddy current effect is, and the greater the voltage that will be fed back to the circuit board to form.

[0076] Similarly, when the rotor approaches the distance sensor 1, the distance sensor 1 gives the rotor a smaller high-frequency excitation force, thereby generating an eddy current on the rotor. The closer the rotor is to the distance sensor 1, the smaller the eddy current effect is, and the smaller the voltage that will be fed back to the circuit board will be.

[0077] That is, the greater the voltage difference between distance sensor 3 and distance sensor 1, the greater the distance d between the rotor's levitation center and distance sensor 1, the greater the corresponding coil current value I of front radial bearing 131, and the closer the rotor is to distance sensor 3. The smaller the voltage difference between distance sensor 3 and distance sensor 1, the smaller the distance d between the rotor's levitation center and distance sensor 1, the smaller the corresponding coil current value i of front radial bearing 131, and the closer the rotor is to distance sensor 1.

[0078] If the coil current value i of the front radial bearing 131 in Figure 9 increases, but the distance d between the rotor's suspension center and the distance sensor 1 decreases, it means that the distance between the distance sensor 3 and the suspension center is too close, that is, the distance between the rotor and the protective bearing is too close at one end of the radial direction of L1, which may damage the compressor. At this time, the corresponding distance d is not considered as the suspension position of the suspension center.

[0079] If the coil current value i of the front radial bearing in Figure 9 is smaller, but the distance d between the rotor's suspension center and the distance sensor 1 is larger, it means that the distance between the distance sensor 1 and the suspension center is too close. In other words, the distance between the rotor and the protective bearing is too close at the other end of the radial direction of L1, which may damage the compressor. At this time, the distance d is not considered as the suspension position of the suspension center.

[0080] Therefore, the present disclosure can determine the coordinate point in FIG10 corresponding to the inflection point appearing in FIG9 , and use the coordinate point as the boundary point of the protective bearing, thereby determining the true protection boundary of the protective bearing.

[0081] In this way, the method and device for determining the magnetic levitation protection boundary disclosed in the present invention can accurately determine the protection boundary corresponding to the protective bearing when the suspension position of the magnetic levitation rotor is adjusted, thereby determining the actual activity space of the magnetic levitation rotor after removing the clearance of the protective bearing, thereby ensuring the normal operation of the compressor.

[0082] Referring to Figure 5 , in one embodiment, the protective bearing 120 includes a front protective bearing 121. The front protective bearing 121 includes a radial detection surface 1211 radially opposed to the magnetic levitation rotor 110 and an axial detection surface 1212 opposed to the end of the magnetic levitation rotor 110. The front protective bearing 121 is configured to provide a protective margin against radial or axial frontal movement of the magnetic levitation rotor 110. In other words, the front protective bearing 121 can be used to define not only the protective margin against radial frontal movement of the magnetic levitation rotor 110, but also the protective margin against axial frontal movement of the magnetic levitation rotor 110.

[0083] The radial detection surface 1211 of the front protective bearing 121 can be opposite to the detection surface of the first detection component installed at the end of the magnetic levitation rotor 110, and the first detection component can be electrically connected to the distance sensor 140 installed on the radial bearing 130, so that the protection boundary of the front radial movement can be detected by the front protective bearing 121.

[0084] The axial detection surface 1212 of the front protective bearing 121 can be opposite to the detection surface of the second detection component installed at the end of the magnetic levitation rotor 110, and the second detection component 112 can also be electrically connected to the distance sensor 140 installed on the radial bearing 130, so that the protection boundary of the axial movement can be detected by the front protective bearing 121.

[0085] The protective bearing 120 includes a rear protective bearing 122. This bearing also includes a radial detection surface 1221 radially opposed to the magnetic levitation rotor 110 and an axial detection surface 1222 opposed to the end of the magnetic levitation rotor 110. The rear protective bearing 122 is used to provide a protective margin against rear radial or axial movement of the magnetic levitation rotor 110. In other words, the front protective bearing 122 not only defines the protective margin against rear radial movement of the magnetic levitation rotor 110, but also against axial movement of the magnetic levitation rotor 110.

[0086] The radial detection surface 1221 of the rear protective bearing 122 can be opposite to the detection surface of the third detection component installed at the end of the magnetic levitation rotor 110, and the third detection component can be electrically connected to the distance sensor 140 installed on the radial bearing 130, so that the protection boundary of the rear radial movement can be detected by the rear protective bearing 122.

[0087] The axial detection surface 1222 of the rear protective bearing 122 can be opposite to the detection surface of the fourth detection component installed at the end of the magnetic levitation rotor 110, and the fourth detection component 114 can also be electrically connected to the distance sensor 140 installed on the radial bearing 130, so that the protection boundary of the axial movement can be detected by the rear protective bearing 122.

[0088] In addition to the above-mentioned connection of the front protection bearing and the rear protection bearing with the distance sensors on the radial bearing through the detection part to determine the protection boundary corresponding to the protection bearing when the magnetic levitation rotor moves radially, and the protection boundary corresponding to the protection bearing when the magnetic levitation rotor moves axially, the present disclosure can also determine the protection boundary of the magnetic levitation rotor in axial movement separately through the axial protection bearing.

[0089] That is, referring to Figure 6, in another embodiment, the protective bearing 120 includes a front protective bearing 121, a rear protective bearing 122 and an axial protective bearing 123. The front protective bearing 121 is used to provide a protective boundary for the radial movement of the magnetic levitation rotor 110 in the front, the rear protective bearing 122 is used to provide a protective boundary for the radial movement of the magnetic levitation rotor 110 in the rear, and the axial protective bearing 123 is used to provide a protective boundary for the axial movement of the magnetic levitation rotor 110.

[0090] Before step 02, the determination method includes:

[0091] 01: Establish a mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing.

[0092] Please refer to FIG11 , the determining device 10 includes a relationship establishing module 11 .

[0093] Step 01 can be implemented by the relationship establishment module 11. That is, the relationship establishment module 11 is used to establish a mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing.

[0094] Specifically, before obtaining the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing of the magnetic levitation centrifugal compressor, the present disclosure can first adjust the distance between the suspension center and the distance sensor, and record the coil current of the radial bearing corresponding to the distance sensor in real time, thereby obtaining the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing.

[0095] The following specifically describes how to determine the protection boundaries of the magnetic suspension rotor 110 in radial and axial movement respectively based on the front protection bearing 121 , the rear protection bearing 122 and / or the axial protection bearing 123 .

[0096] Referring to Figures 5, 6, and 12, in one embodiment of the present disclosure, the protective bearing 120 includes a front protective bearing 121, the radial bearing 130 includes a front radial bearing 131, and the distance sensor 140 includes a first sensor 141 mounted on the front radial bearing 131. Step 01 includes:

[0097] 011: Control the suspension center to move along the radial direction of the front protective bearing, and obtain the first radial distance between the suspension center and the first sensor and the coil current value of the front radial bearing in real time;

[0098] 012: According to the corresponding relationship between the obtained coil current value and the first radial distance, a first radial mapping relationship between the first radial distance and the coil current of the front radial bearing is established.

[0099] Referring to Figure 11 , steps 011 and 012 can be implemented by the relationship establishment module 11. That is, the relationship establishment module 11 is configured to control the first radial distance between the suspension center and the first sensor to move radially along the front protective bearing, obtain the coil current value of the front radial bearing in real time, and establish a first radial mapping relationship between the first radial distance and the coil current of the front radial bearing based on the correspondence between the obtained coil current value and the first radial distance.

[0100] That is to say, referring to FIG10 , the radial direction of the front protective bearing 121 can be evenly divided into L1, L2, L3 and L4 radial directions, that is, a total of 4 radial directions. The suspension center is controlled to move along the above 4 radial directions of the front protective bearing 121 respectively, and the coil current value i of the front radial bearing 131 corresponding to the moving distance of each radial direction is obtained in real time. It should be noted that the interior of the front protective bearing 121 of the embodiment of the present disclosure can also be divided into more radial directions, for example, 6, 8 or 10 radial directions, which are not limited here.

[0101] For example, as shown in Figures 5 or 6 , first sensor 141 can be divided into two sub-sensors 1 and 3, respectively positioned on the outer walls of the front radial bearing at both ends of the radial direction L1, to control the movement of magnetically levitated rotor 110 from sub-sensor 1 toward sub-sensor 3 along radial direction L1. Referring to Figure 9 , first sensor 141 can be pre-designed so that as magnetically levitated rotor 110 approaches sub-sensor 3, the corresponding displacement value output by first sensor 141 decreases, and as it approaches sub-sensor 1, the corresponding displacement value output by first sensor 141 increases. In addition, when the magnetic levitation rotor 110 approaches the sub-sensor 3, the sub-sensor 3 provides a very strong high-frequency excitation force to the magnetic levitation rotor 110, thereby generating an eddy current on the magnetic levitation rotor 110. The closer to the sub-sensor 3, the stronger the eddy current effect, which will be fed back to the circuit board to form a voltage. The voltage value generated by sub-sensor 3 minus the corresponding sub-sensor 1 is equal to the final voltage value of the first sensor 141. Therefore, the closer the magnetic levitation rotor 110 is to the sub-sensor 3, the larger the corresponding voltage value of the first sensor 141. Therefore, the coil current value of the front radial bearing 131 generated by the first sensor 141 is also larger.

[0102] However, when the magnetic levitation rotor 110 is located between the inner and outer walls of the front protective bearing 121 corresponding to one end of sub-sensor 3, it is obstructed by the front protective bearing 121, causing the coil current of the front radial bearing 131 to suddenly decrease, resulting in an inflection point A2 (d2, i2) close to sub-sensor 3. When the magnetic levitation rotor 110 is located between the inner and outer walls of the front protective bearing 121 corresponding to one end of sub-sensor 1, it is obstructed by the front protective bearing 121, causing the coil current of the front radial bearing 131 to gradually decrease. Subsequently, as the magnetic levitation rotor 110 moves away from sub-sensor 1 and gradually approaches sub-sensor 3, the coil current of the front radial bearing 131 gradually decreases and then increases, resulting in an inflection point A1 (d1, i1) close to sub-sensor 1.

[0103] Therefore, A0 (d0, i0) in the curve S1 in Figure 9 can indicate that the suspension center is located at the center point of the forward bearing, and the inflection point A1 (d1, i1) close to sub-sensor 1 and the inflection point A2 (d2, i2) close to sub-sensor 3 can also be determined, where d1 and d2 are the distances between the first sensor 141 and the suspension center point, i1 is the coil current of the front radial bearing 131 when the distance between the first sensor 141 and the suspension center point is d1, and i2 is the coil current of the front radial bearing 131 when the distance between the first sensor 141 and the suspension center point is d2.

[0104] That is, the curve S1 in FIG. 9 represents a first radial mapping relationship between the first radial distance established in the radial direction corresponding to L1 and the coil current of the front radial bearing 131 .

[0105] By analogy, the present disclosure can obtain a first radial mapping relationship between the first radial distances established corresponding to other radial directions of L2, L3, and L4 and the coil current of the front radial bearing 131.

[0106] Conversely, in other embodiments of the present disclosure, the voltage values ​​formed by sub-sensors 1 and 3 and the coil currents of the radial bearings can also be set to have opposite corresponding relationships, thereby obtaining a curve S1' that is completely opposite to that of Figure 9, as shown in Figure 13. Based on this, a first radial mapping relationship between the first radial distance and the coil current of the front radial bearing 131 can also be established.

[0107] After establishing the first radial mapping relationship between the first radial distance and the coil current of the front radial bearing 131, according to the analysis of the principle of generating the inflection point described above, the present disclosure can determine the protection boundary of the magnetic levitation rotor corresponding to the front protective bearing 121 based on the first radial mapping relationship.

[0108] Please refer to FIG14 . The distance sensor includes a first sensor 141 located at the front protective bearing 121 . The determination method includes:

[0109] 021: Obtain the first radial mapping relationship;

[0110] 041: determining, based on the first radial mapping relationship, boundary distances of the suspension center relative to the first sensor in multiple directions when the suspension position of the magnetic suspension rotor changes in multiple directions, and determining, based on the boundary distances, first radial boundary points of the suspension center in multiple directions inside the front protective bearing;

[0111] 061: Form a first radial protection boundary according to the first radial boundary point.

[0112] Please refer to FIG. 8 , step 021 may be implemented by the acquisition module 12 , step 041 may be implemented by the first determination module 14 , and step 061 may be implemented by the second determination module 16 .

[0113] That is, the acquisition module 12 is used to obtain the first radial mapping relationship; the first determination module 14 is used to determine the boundary distance of the suspension center relative to the first sensor in multiple directions when the suspension position of the magnetic levitation rotor changes in multiple directions based on the first radial mapping relationship, and determine the first radial boundary point of the suspension center in multiple directions inside the front protective bearing based on the boundary distance; the second determination module 16 is used to form a first radial protection boundary based on the first radial boundary point.

[0114] Specifically, a first radial mapping relationship is obtained, that is, for example, according to the curve S1 in Figure 9, a correspondence between the first radial distance between the suspension center and the first sensor 141 and the coil current of the front radial bearing 131 can be obtained, d1 and d2 in the S1 curve are the distances between the first sensor 141 and the suspension center point, i1 is the coil current of the front radial bearing 131 when the distance between the first sensor 141 and the suspension center point is d1, and i2 is the coil current of the front radial bearing 131 when the distance between the first sensor 141 and the suspension center point is d2.

[0115] Based on the first radial mapping relationship, the boundary distances of the suspension center relative to the first sensor in multiple directions when the suspension position of the magnetic levitation rotor 110 changes in multiple directions are determined, and the first radial boundary points of the suspension center in multiple directions within the front protective bearing are determined based on the boundary distances. For example, an inflection point A1 (d1, i1) near sub-sensor 1 and an inflection point A2 (d2, i2) near sub-sensor 3 can be obtained. These two inflection points are the first radial boundary points in the L1 radial direction of the front protective bearing 121. At this time, the boundary distances of the suspension center in the L1 radial direction within the front protective bearing are d1 and d2, respectively. In addition, since the inflection points A1 (d1, i1) and A2 (d2, i2) in Figure 9 correspond to points B1 (x1, y1) and B2 (x2, y2) in the two-dimensional bearing coordinate system of Figure 10, respectively, points B1 (x1, y1) and B2 (x2, y2) are the finally determined first radial boundary points. In the two-dimensional bearing coordinate system of FIG10 , the horizontal coordinate is represented by FX, and the vertical coordinate is represented by FY.

[0116] The first radial protection boundary is formed according to the first radial boundary point. Since one radial direction of the front protection bearing 121 can determine the corresponding two first radial boundary points, multiple first radial boundary points corresponding to different directions can be determined by dividing into different radial directions. By analogy, the radial front protection bearing boundary points of L2, L3 and L4 in Figure 10 can be obtained, corresponding to B3 (x3, y3), B4 (x4, y4), B5 (x5, y5), B6 ​​(x6, y6), B7 (x7, y7), and B8 (x8, y8) in Figure 10.

[0117] In this way, the embodiment of the present disclosure can sequentially connect all the obtained first radial boundary points in FIG. 10 to form a first radial protection boundary.

[0118] 5 and 15 , in another embodiment of the present disclosure, the front protective bearing 121 includes an axial detection surface 1212 opposite to the end of the magnetic levitation rotor 110 . The front protective bearing 121 is further configured to provide a protective boundary for axial movement of the magnetic levitation rotor 110 . Step 01 includes:

[0119] 013: Control the suspension center to move along the axial direction of the front protective bearing, and obtain the first axial distance between the suspension center and the first sensor and the coil current value of the front radial bearing in real time;

[0120] 014: According to the corresponding relationship between the obtained coil current value and the first axial distance, a first axial mapping relationship between the first axial distance and the coil current of the front radial bearing is established.

[0121] Referring to Figure 11 , steps 013 and 014 can be implemented by the relationship establishment module 11. Specifically, the relationship establishment module 11 is configured to control the axial movement of the suspension center along the front protective bearing, acquire a first axial distance between the suspension center and the first sensor and a coil current value of the front radial bearing in real time, and establish a first axial mapping relationship between the first axial distance and the coil current of the front radial bearing based on the correspondence between the acquired coil current value and the first axial distance.

[0122] Specifically, referring to FIG16 , the rotation direction of the magnetic levitation rotor 110 can also be defined as a total of 8 rotation directions, including Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8. The suspension center is controlled to move along the axial direction of the front protective bearing 121 corresponding to the above 8 rotation directions of the magnetic levitation rotor 110, and the coil current value i of the front radial bearing 131 corresponding to each axial movement distance is obtained in real time. It should be noted that the interior of the magnetic levitation rotor 110 of the embodiment of the present disclosure can also be divided into more rotation directions, for example, 6, 8 or 10 rotation directions, which are not limited here.

[0123] That is, taking one rotation direction Z1 as an example, the present disclosure can divide the axial movement distance into K equal parts at equal intervals or into K equal parts from largest to smallest intervals. The levitation position of the magnetically levitated rotor 110 is adjusted K times, and the coil current values ​​i1…ik of the front radial bearing 131 are recorded each time to form a current-position curve, such as curve S3 shown in Figure 17. Similarly, the current-position curves corresponding to the magnetically levitated rotor 110 in other rotation directions Z2 to Z8 can be obtained.

[0124] In this way, the present invention can move the suspension center of the magnetic levitation rotor 110 along the axial direction of the front protective bearing 121 at equal intervals or at intervals from large to small, thereby obtaining the correspondence between the coil current value of the front radial bearing 131 and the first axial distance between the suspension center and the first sensor 141, thereby establishing a first axial mapping relationship.

[0125] Referring to FIG. 18 , the determination method includes:

[0126] 023: Get the first axial mapping relationship;

[0127] 043: Determine, based on the first axial mapping relationship, a plurality of bearing boundary distances at which the levitation center of the magnetic levitation rotor is located in the axial movement direction of the magnetic levitation rotor, so as to determine a first axial boundary point of the levitation center in the rotor axial direction;

[0128] 063: Form a first axial protection boundary according to the first axial boundary point.

[0129] Please refer to FIG. 8 , step 023 may be implemented by the acquisition module 12 , step 043 may be implemented by the first determination module 14 , and step 063 may be implemented by the second determination module 16 .

[0130] That is, the acquisition module 12 is used to obtain the first axial mapping relationship; the first determination module 14 is used to determine the multiple bearing boundary distances at which the suspension center of the magnetic levitation rotor is located in the axial movement direction of the magnetic levitation rotor based on the first axial mapping relationship, so as to determine the first axial boundary point of the suspension center in the axial direction of the rotor; the second determination module 16 is used to form a first axial protection boundary based on the first axial boundary point.

[0131] Specifically, the first axial mapping relationship is obtained. That is, after establishing the first axial mapping relationship between the first axial distance and the coil current value, the first axial mapping relationship can be obtained. That is, for example, based on curve S3 in FIG17 , the corresponding relationship between the first axial distance between the suspension center and the first sensor 141 and the coil current of the front radial bearing 131 can be obtained. In curve S3, d5 and d6 are the distances from the first sensor 141 to the suspension center point, i5 is the coil current of the front radial bearing 131 when the distance from the first sensor 141 to the suspension center point is d5, and i6 is the coil current of the front radial bearing 131 when the distance from the first sensor 141 to the suspension center point is d6.

[0132] The suspension center of the magnetic suspension rotor 110 is located at multiple bearing boundary distances in the axial movement direction of the magnetic suspension rotor 110 according to the first axial mapping relationship, so as to determine the axial boundary point of the suspension center in the rotor axial direction.

[0133] For example, the magnetic levitation rotor 110 is rotated to the direction Z1, and the suspension center position and the coil current of the front radial bearing 131 are recorded. The suspension center position is marked as the corresponding point F0 (x0, 0) in the one-dimensional bearing coordinate system.

[0134] In curve S3, we can find inflection points G1 (d5, i5) near sub-sensor 9 and G2 (d6, i6) near sub-sensor 10. As shown in Figure 17, these two inflection points are the corresponding axial boundary points of the levitation center when the magnetic levitation rotor rotates in the Z1 direction. At this time, the axial boundary distances of the levitation center within the front protective bearing 121 are d5 and d6, respectively. Furthermore, since the inflection points G1 (d5, i5) and G2 (d6, i6) in Figure 17 correspond to points F1 (x1, 0) and F2 (x2, 0) in the one-dimensional bearing coordinate system, respectively, points F1 (x1, 0) and F2 (x2, 0) are the axial boundary points determined when the rotation direction is Z1. Here, the bearing boundary distance d5 = x0 - x1, and the bearing boundary distance d6 = x2 - x0.

[0135] Since two corresponding first axial boundary points can be determined for a fixed rotational position of the magnetic levitation rotor 110, multiple first axial boundary points corresponding to different rotational directions can be determined for the magnetic levitation rotor 110 at different rotational positions. Similarly, the first axial boundary points of other rotational directions of Z2, Z3, Z4, Z5, Z6, Z7, and Z8 in FIG16 can be obtained, corresponding to points F3(x3,0), F4(x4,0), F5(x5,0), F6(x6,0), F7(x7,0), F8(x8,0), F9(x9,0), F10(x10,0), F11(x11,0), F12(x12,0), F13(x13,0), F14(x14,0), F15(x15,0), and F16(x16,0) in the one-dimensional bearing coordinate system.

[0136] Afterwards, the first axial protection boundary is formed based on the first axial boundary point. That is, the present disclosure can select the points on the left and right sides of x0 closest to x0 from the above coordinate points as the real axial protection gap boundary, that is, select the two axial coordinate points closest to x0, for example, they can be F3 (x3, 0) and F4 (x4, 0), and then use F3 (x3, 0) and F4 (x4, 0) as the first axial protection boundary. At this time, the bearing boundary distance d7 = x0-x3, the bearing boundary distance d8 = x4-x0, and the values ​​of d7 and d8 are the smallest compared to other distance values.

[0137] In this way, the present disclosure can obtain the first axial protection boundary according to the axial boundary point.

[0138] 5 or 6 , in another embodiment of the present disclosure, the protective bearing 120 includes a rear protective bearing 122 , and the distance sensor 140 includes a second sensor 142 mounted on the rear radial bearing 132 . Referring to FIG. 19 , step 01 includes:

[0139] 013: Control the second radial distance between the suspension center and the second sensor to move radially along the rear protective bearing, and obtain the coil current value of the front radial bearing in real time;

[0140] 014: According to the corresponding relationship between the obtained coil current value and the second radial distance, a second radial mapping relationship between the second radial distance and the coil current of the rear radial bearing is established.

[0141] Referring to Figure 11 , steps 011 and 012 can be implemented by the relationship establishment module 11. Specifically, the relationship establishment module 11 is configured to control the second radial distance between the suspension center and the second sensor to move radially along the rear protective bearing, thereby acquiring the coil current value of the front radial bearing in real time; and, based on the correspondence between the acquired coil current value and the second radial distance, establish a second radial mapping relationship between the second radial distance and the coil current of the rear radial bearing.

[0142] That is to say, referring to FIG. 20 , the radial direction of the rear protective bearing 122 can also be evenly divided into L1, L2, L3, and L4 radial directions, that is, a total of four radial directions. The suspension center is controlled to move along the above four radial directions of the rear protective bearing 122, and the coil current value i of the rear radial bearing 132 corresponding to the moving distance of each radial direction is obtained in real time. It should be noted that the interior of the rear protective bearing 122 of the embodiment of the present disclosure can also be divided into more radial directions, for example, 6, 8, or 10 radial directions, which are not limited here.

[0143] For example, as shown in Figures 5 or 6 , second sensor 142 can be divided into two sub-sensors 5 and 7, respectively positioned on the outer walls of rear radial bearing 122 at either end of the radial direction L1, to control the movement of magnetically levitated rotor 110 from sub-sensor 5 toward sub-sensor 7 along radial direction L1. Similar to first sensor 141, and referring to Figure 21 , second sensor 142 can also be designed so that when magnetically levitated rotor 110 approaches sub-sensor 5, the corresponding displacement value output by second sensor 142 decreases, while when it approaches sub-sensor 7, the corresponding displacement value output by first sensor 141 increases. In addition, when the magnetic levitation rotor 110 approaches the sub-sensor 7, the sub-sensor 7 gives the magnetic levitation rotor a very strong high-frequency excitation force, thereby generating an eddy current on the magnetic levitation rotor 110. The closer to the sub-sensor 7, the stronger the eddy current effect, which will be fed back to the circuit board to form a voltage. The voltage value generated by sub-sensor 7 minus the corresponding sub-sensor 5 is equal to the final voltage value of the second sensor 142. Therefore, the closer the magnetic levitation rotor 110 is to the sub-sensor 7, the larger the corresponding voltage value of the second sensor 142. Therefore, the coil current value of the rear radial bearing generated by the second sensor 142 is also larger.

[0144] However, when the magnetic levitation rotor 110 is located between the inner and outer walls of the rear protective bearing 122 corresponding to one end of sub-sensor 3, it is obstructed by rear protective bearing 122, causing the coil current of rear radial bearing 132 to suddenly decrease, resulting in an inflection point C2 (d4, i4) close to sub-sensor 7. When the magnetic levitation rotor 110 is located between the inner and outer walls of the rear protective bearing 122 corresponding to one end of sub-sensor 5, it is obstructed by rear protective bearing 122, causing the coil current of rear radial bearing 132 to gradually decrease. As the magnetic levitation rotor 110 moves away from sub-sensor 5 and gradually approaches sub-sensor 7, the coil current of rear radial bearing 132 gradually decreases and then increases, resulting in an inflection point C1 (d3, i3) close to sub-sensor 5.

[0145] Therefore, C0 (d0, i0) in curve S2 in Figure 21 can indicate that the suspension center is located at the center point of the forward bearing, and the inflection point C1 (d3, i3) close to sub-sensor 5 and the inflection point C2 (d4, i4) close to sub-sensor 7 can also be determined, where d3 and d4 are the distances between the second sensor 142 and the suspension center point, i3 is the coil current of the rear radial bearing 132 when the distance between the second sensor 142 and the suspension center point is d3, and i4 is the coil current of the rear radial bearing 132 when the distance between the second sensor 142 and the suspension center point is d4.

[0146] That is, the curve S2 in FIG. 21 represents the second radial mapping relationship between the second radial distance corresponding to the radial direction of L1 and the coil current of the rear radial bearing 132 .

[0147] By analogy, the present disclosure can obtain a second radial mapping relationship between the second radial distances established corresponding to other radial directions of L2, L3, and L4 and the coil current of the rear radial bearing 132.

[0148] Conversely, in other embodiments of the present disclosure, the voltage values ​​formed by sub-sensors 5 and 7 and the coil currents of the radial bearings can also be set to have opposite corresponding relationships, thereby obtaining a curve S2' that is completely opposite to that of Figure 21. Based on this, a second radial mapping relationship can also be established between the second radial distance and the coil current of the rear radial bearing 132.

[0149] After establishing a second radial mapping relationship between the second radial distance and the coil current of the rear radial bearing 132, according to the analysis of the principle of generating the inflection point described above, the present disclosure can determine the protection boundary of the magnetic levitation rotor 110 corresponding to the rear protective bearing 122 based on the second radial mapping relationship.

[0150] Referring to FIG. 22 , in certain embodiments of the present disclosure, the determination method includes:

[0151] 024: Get the second radial mapping relationship;

[0152] 044: Determine, based on the second radial mapping relationship, the boundary distances of the suspension center relative to the second sensor in multiple directions when the suspension position of the magnetic suspension rotor changes in multiple directions, and determine, based on the boundary distances, the second radial boundary points of the suspension center in multiple directions inside the rear protective bearing;

[0153] 064: Form a second radial protection boundary according to the second radial boundary point.

[0154] Please refer to FIG. 8 , step 024 may be implemented by the acquisition module 12 , step 044 may be implemented by the first determination module 14 , and step 064 may be implemented by the second determination module 16 .

[0155] That is, the acquisition module 12 is used to obtain the second radial mapping relationship; the first determination module 14 is used to determine the boundary distance of the suspension center relative to the second sensor in multiple directions when the suspension position of the magnetic levitation rotor changes in multiple directions based on the second radial mapping relationship, and determine the second radial boundary point of the suspension center in multiple directions inside the rear protection bearing based on the boundary distance; the second determination module 16 is used to form a second radial protection boundary based on the second radial boundary point.

[0156] Specifically, the second radial mapping relationship is obtained, that is, for example, according to the curve S2 in Figure 21, the correspondence between the distance between the suspension center and the second sensor 142 and the coil current of the rear radial bearing 132 can be obtained, d3 and d4 in the S2 curve are the distances between the second sensor 142 and the suspension center point, i3 is the coil current of the rear radial bearing 132 when the distance between the second sensor 142 and the suspension center point is d3, and i4 is the coil current of the rear radial bearing 132 when the distance between the second sensor 142 and the suspension center point is d4.

[0157] Based on the second radial mapping relationship, the boundary distances of the suspension center relative to the second sensor 142 in multiple directions when the magnetic levitation rotor 110 changes its suspension position in multiple directions are determined, and the second radial boundary points of the suspension center in multiple directions within the rear protective bearing 122 are determined based on the boundary distances. For example, the inflection point C1 (d3, i3) near sub-sensor 5 and the inflection point C2 (d4, i4) near sub-sensor 7 can be obtained. These two inflection points are the second radial boundary points in the L1 radial direction of the front protective bearing 121. At this time, the boundary distances of the suspension center in the L1 radial direction within the rear protective bearing 122 are d3 and d4, respectively. In addition, since the inflection points C1 (d3, i3) and C2 (d4, i4) in Figure 21 correspond to points D1 (x1, y1) and D2 (x2, y2) in the two-dimensional bearing coordinate system of Figure 20, respectively, points D1 (x1, y1) and D2 (x2, y2) are the final second radial boundary points. In the two-dimensional bearing coordinate system of FIG20 , the horizontal coordinate is represented by RX, and the vertical coordinate is represented by RY.

[0158] The second radial protection boundary is formed according to the second radial boundary point. Since one radial direction of the rear protection bearing 122 can determine the corresponding two second radial boundary points, multiple second radial boundary points corresponding to different directions can be determined by dividing into different radial directions. By analogy, the radial rear protection bearing boundary points of L2, L3 and L4 in Figure 20 can be obtained, corresponding to D3 (x3, y3), D4 (x4, y4), D5 (x5, y5), D6 (x6, y6), D7 (x7, y7), and D8 (x8, y8) in Figure 20.

[0159] In this way, the embodiment of the present disclosure can sequentially connect all the obtained second radial boundary points in FIG. 20 to form a protection boundary.

[0160] 5 and 23 , in another embodiment of the present disclosure, the rear protective bearing 122 includes an axial detection surface 1222 opposite to the end of the magnetic levitation rotor 110 . The rear protective bearing 122 is further configured to provide a protective boundary for axial movement of the magnetic levitation rotor 110 . Step 01 includes:

[0161] 015: Control the suspension center to move along the axial direction of the rear protective bearing, and obtain the second axial distance between the suspension center and the second sensor and the coil current value of the rear radial bearing in real time;

[0162] 016: According to the corresponding relationship between the obtained coil current value and the second axial distance, a second axial mapping relationship between the second axial distance and the coil current of the rear radial bearing is established.

[0163] Referring to Figure 11, steps 015 and 016 can be implemented by the relationship establishment module 11. Specifically, the relationship establishment module 11 is configured to control the axial movement of the suspension center along the rear protective bearing, acquire the first axial distance between the suspension center and the second sensor and the coil current value of the rear radial bearing in real time, and establish a first axial mapping relationship between the second axial distance and the coil current of the rear radial bearing based on the correspondence between the acquired coil current value and the second axial distance.

[0164] Specifically, the rotation direction of the magnetic levitation rotor 110 can also be defined as a total of 8 rotation directions, including Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8. The suspension center is controlled to move along the axial direction of the rear protective bearing 122 corresponding to the above 8 rotation directions of the magnetic levitation rotor 110, and the coil current value i of the rear radial bearing 132 corresponding to each axial movement distance is obtained in real time. It should be noted that the interior of the magnetic levitation rotor 110 of the embodiment of the present disclosure can also be divided into more rotation directions, for example, 6, 8 or 10 rotation directions, which are not limited here.

[0165] That is, taking one rotation direction Z1 as an example, the present disclosure can divide the axial movement distance into K2 equal parts at equal intervals or into K2 equal parts from largest to smallest intervals. The levitation position of the magnetically levitated rotor 110 is adjusted K2 times. The coil current values ​​i1…ik2 of the radial bearing 132 after each adjustment are recorded to form a current-position curve similar to curve S3 shown in Figure 17. Similarly, current-position curves corresponding to the magnetically levitated rotor 110 in other rotation directions Z2 to Z8 can be obtained.

[0166] In this way, the present disclosure can move the suspension center of the magnetic levitation rotor 110 along the axial direction of the rear protective bearing 122 at equal intervals or at intervals from large to small, thereby obtaining the correspondence between the coil current value of the rear radial bearing 132 and the second axial distance between the suspension center and the second sensor 142, thereby establishing a second axial mapping relationship.

[0167] Referring to FIG. 24 , the determination method includes:

[0168] 025: Get the second axis mapping relationship;

[0169] 045: Determine, based on the second axial mapping relationship, a plurality of bearing boundary distances at which the levitation center of the magnetic levitation rotor is located in the axial movement direction of the magnetic levitation rotor, so as to determine a second axial boundary point of the levitation center in the axial direction of the rotor;

[0170] 065: Form a second axial protection boundary based on the second axial boundary point.

[0171] Please refer to FIG. 8 , step 025 may be implemented by the acquisition module 12 , step 045 may be implemented by the first determination module 14 , and step 065 may be implemented by the second determination module 16 .

[0172] That is, the acquisition module 12 is used to obtain the second axial mapping relationship; the first determination module 14 is used to determine the multiple bearing boundary distances at which the suspension center of the magnetic levitation rotor is located in the axial movement direction of the magnetic levitation rotor based on the second axial mapping relationship, so as to determine the second axial boundary point of the suspension center in the axial direction of the rotor; the second determination module 16 is used to form a second axial protection boundary based on the second axial boundary point.

[0173] Specifically, the specific content of obtaining the second axial protection boundary at this time is similar to the process of the axial detection surface of the front protection bearing 121, which will not be repeated here.

[0174] In this way, the present disclosure can obtain the second axial protection boundary according to the second axial boundary point.

[0175] In one embodiment of the present disclosure, in order to control the distance between the suspension center of the magnetic levitation rotor 110 and the distance sensor 140 to move along the radial or axial direction of the protective bearing 120, the coil current value of the radial bearing 130 is obtained in real time, that is, step 01 includes: controlling the distance between the suspension center and the distance sensor 140 to move along the radial or axial direction of the protective bearing 120 according to a first spacing distance, and obtaining in real time the coil current value of the radial bearing 130 when the suspension center moves at an equal distance.

[0176] The protective bearing 120 includes a front protective bearing 121 and a rear protective bearing 122 . The radial bearing 130 includes a front radial bearing 131 and a rear radial bearing 132 .

[0177] That is, for both the front protective bearing 121 and the rear protective bearing 122, the radial direction L1 can be divided into N equal parts according to the first spacing distance. The suspension position is adjusted N times using the radial direction L1 as the path. The coil current value i1...in of the front radial bearing 131 or the rear radial bearing 132 is recorded each time to form a current-position curve, as shown in Figure 9 or Figure 21.

[0178] In this way, the present disclosure can move the suspension center radially at equal intervals, thereby obtaining the correspondence between the coil current value of the front protective bearing 121 or the rear radial bearing 122 and the distance between the suspension center and the distance sensor 140, thereby establishing a first radial mapping relationship or a second radial mapping relationship.

[0179] In another embodiment of the present disclosure, the distance between the suspension center of the magnetic levitation rotor 110 and the distance sensor 140 is controlled to move along the radial direction of the protective bearing 120, and the coil current value of the radial bearing 130 is obtained in real time. That is, step 01 includes: controlling the distance between the suspension center and the distance sensor 140 to move along the radial or axial direction of the protective bearing 120 according to the interval distance from large to small, and obtaining in real time the coil current value of the radial bearing 130 when the suspension center moves at different distances.

[0180] The protective bearing 120 includes a front protective bearing 121 and a rear protective bearing 122 . The radial bearing 130 includes a front radial bearing 131 and a rear radial bearing 132 .

[0181] For example, for both the front protective bearing 121 and the rear protective bearing 122, the radial direction L1 can be divided into M parts, starting from the center point of the front protective bearing 121 or the rear protective bearing 122, at decreasing intervals. The suspension position is adjusted M times using the radial direction L1 as the adjustment path. The coil current values ​​i1...im of the front protective bearing 121 or the rear radial bearing 122 are recorded each time to form a current-position curve, which can also be formed as shown in FIG9 or FIG21.

[0182] In this way, the present disclosure may or may not be adjusted in equal parts. The step size may be relatively large when the suspension center is first adjusted, and then the step size may be gradually reduced, so as to obtain the correspondence between the coil current value of the front radial bearing 131 or the rear radial bearing 132 and the distance between the suspension center and the distance sensor 140, and at the same time, the efficiency of obtaining the corresponding relationship can be improved.

[0183] It should be noted that in certain embodiments of the present disclosure, the initial movement position of the suspension center can be defaulted to the center position of the front protection bearing 121 or the rear protection bearing 122. In other embodiments of the present disclosure, the initial movement position of the suspension center can also be other positions, which is not limited here.

[0184] Specifically, the present disclosure divides the front and rear protection bearings into eight evenly spaced zones, each zone having an angle of 45°, with boundary lines L1 to L4, and the center of each zone being the suspension center. The following description will take the evenly spaced front protection bearing 121 as an example.

[0185] Then, the position of the suspension center point and the current are recorded, marked as A0 (d0, i0) in Figure 9, and the two-dimensional bearing coordinate system is B0 (x0, y0).

[0186] Next, for the front protective bearing 121, L1 is divided into N equal parts. L1 is used as the position adjustment path, and adjustments are made N times. The suspension current i1...in is recorded each time to form a current-position curve, as shown in FIG9 .

[0187] Then, find the inflection points A1(d1, i1) and A2(d2, i2) corresponding to the current curve, where d1 and d2 are the distances from the sensor to the center of the zone, corresponding to B1(x1, y1) and B2(x2, y2) in Figure 10.

[0188] in:

[0189] Afterwards, similarly, find the corresponding inflection points of L2, L3, and L4 and their distances from the center point, which correspond to B3 (x3, y3), B4 (x4, y4), B5 (x5, y5), B6 ​​(x6, y6), B7 (x7, y7), and B8 (x8, y8) in Figure 10.

[0190] Fitting B1-B8 to a curve, the dashed line in Figure 10, represents the true protective clearance boundary of the front protective bearing 121 after clearance removal. Similarly, the true protective clearance boundary of the rear bearing is obtained by fitting D1-D8 to a curve, the dashed line in Figure 20, representing the true protective clearance boundary of the rear protective bearing 122 after clearance removal. Compared to the protective clearance boundaries shown in Figures 2 and 3 of the related art, the true protective clearance boundary of the front protective bearing 121 determined in the present disclosure is shown in Figure 25, and the true protective clearance boundary of the rear protective bearing 122 determined in the present disclosure is shown in Figure 26.

[0191] In certain embodiments of the present disclosure, the distance sensor 140 includes a third sensor 143 mounted on the end of the magnetically suspended rotor 110 or a third sensor 143 disposed on the front radial bearing 131 or the rear radial bearing 132. Referring to FIG. 27 , step 01 includes:

[0192] 017: Control the levitation center to move axially along at least one rotation direction of the magnetic levitation rotor according to a second interval, and obtain in real time the coil current of the front radial bearing or the rear radial bearing and the third axial distance between the levitation center and the third sensor when the levitation center moves at equal intervals;

[0193] 018: Establish a third axial mapping relationship according to the third axial distance and the coil current value.

[0194] Referring to Figure 11 , steps 017 and 018 can be implemented by relationship establishment module 11. Specifically, relationship establishment module 11 is configured to control the levitation center to move axially along at least one rotational direction of the magnetic levitation rotor at a second interval, acquire in real time the coil current of the front radial bearing or the rear radial bearing when the levitation center moves at equal intervals, and establish a third axial mapping relationship based on the third axial distance and the coil current value.

[0195] Specifically, the distance sensor 140 is installed on the third sensor 143 at the end of the magnetic levitation rotor 110 or the third sensor 143 is set on the front radial bearing 131 or the rear radial bearing 132, which means that the third sensor 143 can be located on the outer wall of the radial bearing 130, or it can be fixed at a fixed position corresponding to the end of the magnetic levitation rotor 110 instead of being located on the outer wall of the radial bearing 130.

[0196] The third sensor 143 can be equipped with only one sub-sensor 9 to detect the distance between the suspension center and the sensor and record the axial coil current, or two sub-sensors can be equipped with sub-sensor 9 and sub-sensor 10 (similar to the distance detection principle described above) to detect the distance between the suspension center and the sensor and record the coil current of the front radial bearing or the rear radial bearing.

[0197] When two sub-sensors, one at each end of the magnetically suspended rotor, are provided, a linear relationship between the coil current of the front radial bearing or the rear radial bearing and the third axial distance can be obtained, as shown in FIG9 . This disclosure uses the example of providing one sub-sensor at each end of the magnetically suspended rotor.

[0198] When only one sub-sensor is set at one end of the magnetic levitation rotor, the obtained curve relationship between the coil current of the front radial bearing 131 or the rear radial bearing 132 and the distance between the suspension center and the sub-sensor can be converted through relevant calculations to obtain a linear relationship between the coil current of the front radial bearing 131 or the rear radial bearing 132 and the third axial distance.

[0199] For details, please refer to FIG16 . The rotation direction of the magnetic levitation rotor 110 can also be defined as eight rotation directions, including Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8. The suspension center is controlled to move along the axial directions corresponding to the eight rotation directions of the magnetic levitation rotor 110, and the coil current value i of the front radial bearing 131 or the rear radial bearing 132 corresponding to the movement distance of each axial direction is obtained in real time. It should be noted that the interior of the magnetic levitation rotor 110 of the embodiment of the present disclosure can also be divided into more rotation directions, for example, 6, 8, or 10 rotation directions, which are not limited here.

[0200] That is, taking one rotation direction Z1 as an example, the present disclosure can divide the axial movement distance into K3 equal parts based on the second spacing distance. The levitation position of the magnetically levitated rotor 110 is adjusted K3 times. The coil current values ​​i1…ik3 of the front radial bearing 131 or rear radial bearing 132 are recorded each time to form a current-position curve, such as curve S3 shown in Figure 17. Similarly, current-position curves corresponding to the magnetically levitated rotor 110 in other rotation directions Z2 through Z8 can be obtained.

[0201] In this way, the present disclosure can move the suspension center axially at equal intervals, thereby obtaining the correspondence between the coil current value of the front radial bearing 131 or the rear radial bearing 132 and the third axial distance between the suspension center and the distance sensor, thereby establishing a third axial mapping relationship.

[0202] In addition, in another embodiment of the present disclosure, referring to FIG. 28 , step 01 includes:

[0203] 0191: Control the levitation center to move along the axial direction of at least one rotation direction of the magnetic levitation rotor according to the interval distance from large to small, and obtain in real time the coil current value of the axial and radial bearings and the third axial distance between the levitation center and the third sensor when the levitation center moves at different distances;

[0204] 0192: Establish a third axial mapping relationship according to the third axial distance and the coil current value.

[0205] Referring to Figure 11, steps 0191 and 0192 can be implemented by relationship establishment module 11. Specifically, relationship establishment module 11 is configured to control the levitation center to move axially along at least one rotational direction of the magnetic levitation rotor at intervals from largest to smallest, acquire in real time the coil current values ​​of the axial and radial bearings of the magnetic levitation centrifugal compressor and the third axial distance between the levitation center and the third sensor when the levitation center moves at different distances, and establish a third axial mapping relationship based on the third axial distance and the coil current values.

[0206] For ease of understanding, let's first use the example of the magnetic levitation rotor 110 rotating in the Z1 direction. The rotor is rotated in the Z1 direction, and the levitation center of the magnetic levitation rotor 110 is controlled to move axially K4 times from its initial position, at decreasing intervals. The coil current values ​​i1…ik4 of the front radial bearing 131 or rear radial bearing 132 are recorded for each movement, forming a current-position curve S3, as shown in FIG17 . This establishes a third axial mapping relationship between the third axial distance and the coil current value.

[0207] By analogy, the current position curves corresponding to the magnetic suspension rotor 110 in other rotation directions Z2 to Z8 can be obtained.

[0208] In this way, the present disclosure may or may not be adjusted in equal parts. The step size may be relatively large when the suspension center is first adjusted, and then the step size may be gradually reduced, so as to obtain the correspondence between the coil current value of the front radial bearing 131 or the rear radial bearing 132 and the distance between the suspension center and the third sensor 143, and at the same time, the efficiency of obtaining the corresponding relationship can be improved.

[0209] In certain embodiments of the present disclosure, referring to FIG. 29 , the determination method includes:

[0210] 026: Get the third axis mapping relationship;

[0211] 046: Determine, based on the third axial mapping relationship, a plurality of bearing boundary distances at which the levitation center of the magnetic levitation rotor is located in the axial movement direction of the magnetic levitation rotor, so as to determine an axial boundary point of the levitation center in the rotor axial direction;

[0212] 066: Form a third protective bearing boundary based on the axial boundary point.

[0213] Please refer to FIG. 8 , step 026 may be implemented by the acquisition module 12 , step 046 may be implemented by the first determination module 14 , and step 066 may be implemented by the second determination module 16 .

[0214] That is, the acquisition module 12 is used to obtain the third axial mapping relationship; the first determination module 14 is used to obtain the third axial mapping relationship; the first determination module 14 is used to determine the multiple bearing boundary distances of the suspension center of the magnetic levitation rotor in the axial movement direction of the magnetic levitation rotor based on the third axial mapping relationship, so as to determine the axial boundary point of the suspension center in the axial direction of the rotor; the second determination module 16 is used to form a third protective bearing boundary based on the axial boundary point.

[0215] That is to say, after establishing the third axial mapping relationship between the third axial distance and the coil current value, the third axial mapping relationship can be obtained, that is, for example, according to the curve S3 in 17, the correspondence between the third axial distance between the suspension center and the third sensor 143 and the coil current of the front radial bearing 131 or the rear radial bearing 132 of the magnetic levitation centrifugal compressor can be obtained, d5 and d6 in the S3 curve are the distances between the third sensor 143 and the suspension center point, i5 is the coil current of the front radial bearing 131 or the rear radial bearing 132 when the distance between the third sensor 143 and the suspension center point is d5, and i6 is the coil current of the front radial bearing 131 or the rear radial bearing 132 when the distance between the third sensor 143 and the suspension center point is d6.

[0216] The suspension center of the magnetic suspension rotor 110 is located at multiple bearing boundary distances in the axial movement direction of the magnetic suspension rotor 110 according to the third axial mapping relationship, so as to determine the axial boundary point of the suspension center in the rotor axial direction.

[0217] For example, as shown in FIG16 , the magnetic levitation rotor is rotated to the direction Z1, and the position of the levitation center point and the coil current of the front radial bearing 131 or the rear radial bearing 132 at this time are recorded. The position of the levitation center point can also be obtained, and the corresponding one-dimensional bearing coordinate system point is marked as F0 (x0, 0).

[0218] In curve S3, we can find inflection points G1 (d5, i5) near sub-sensor 9 and G2 (d6, i6) near sub-sensor 10. As shown in Figure 16, these two inflection points are the corresponding axial boundary points of the levitation center of the magnetic levitation rotor 110 when the rotation direction is Z1. At this time, the axial boundary distances of the levitation center within the front protective bearing 121 are d5 and d6, respectively. Furthermore, since the inflection points G1 (d5, i5) and G2 (d6, i6) in Figure 17 correspond to points F1 (x1, 0) and F2 (x2, 0) in the one-dimensional bearing coordinate system, respectively, points F1 (x1, 0) and F2 (x2, 0) are the axial boundary points determined when the rotation direction is Z1. Here, the bearing boundary distance d5 = x0 - x1, and the bearing boundary distance d6 = x2 - x0.

[0219] Since the rotation direction of the magnetic levitation rotor 110 can determine two corresponding axial boundary points, multiple axial boundary points corresponding to different rotation directions can be determined. Similarly, the axial boundary points of other rotation directions of Z2, Z3, Z4, Z5, Z6, Z7, and Z8 in Figure 21 can be obtained, corresponding to points F3(x3,0), F4(x4,0), F5(x5,0), F6(x6,0), F7(x7,0), F8(x8,0), F9(x9,0), F10(x10,0), F11(x11,0), F12(x12,0), F13(x13,0), F14(x14,0), F15(x15,0), and F16(x16,0) in the one-dimensional bearing coordinate system.

[0220] Afterwards, a third protective bearing boundary is formed based on the axial boundary points. That is, the present disclosure can select the points on the left and right sides of x0 closest to x0 from the above coordinate points as the axial true protective gap boundary, that is, select the two axial coordinate points closest to x0, for example, they can be F3 (x3, 0) and F4 (x4, 0), and then use F3 (x3, 0) and F4 (x4, 0) as the third protective bearing boundary. At this time, the bearing boundary distance d7 = x0-x3, the bearing boundary distance d8 = x4-x0, and the values ​​of d7 and d8 are the smallest compared to other distance values.

[0221] In this way, the present disclosure can obtain the third protective bearing boundary according to the axial boundary point.

[0222] In detail, please refer to Figure 16. The axial direction of the magnetic levitation rotor 110 can also be defined as a total of 8 rotation directions corresponding to different rotation positions, including Z1, Z2, Z3, Z4, Z5, Z6, Z7, and Z8. The suspension center is controlled to move axially along the above 8 rotation directions of the rear protective bearing 122, and the coil current value i of the rear radial bearing 132 corresponding to each radial movement distance is obtained in real time. It should be noted that the interior of the magnetic levitation rotor 110 of the embodiment of the present disclosure can also be divided into more rotation directions, for example, 10, 12, or 14 rotation directions, which are not limited here.

[0223] Then, the magnetic levitation rotor is rotated to the direction Z1, and the position of the levitation center point and the coil current of the front radial bearing 131 or the rear radial bearing 132 at this time are recorded. The center point E0 (d0, i0) of the curve marked as similar to A0 (d0, i0) in Figure 9 can also be obtained, but the point of the one-dimensional bearing coordinate system corresponding to the levitation center point position is F0 (x0, 0).

[0224] Next, when the magnetically suspended rotor is in direction Z1, the axial suspension position of the magnetically suspended rotor is adjusted K times in total, and the suspension current i1…ik is recorded each time to form a current position curve S3, which is similar to the curve S1 shown in FIG9 and the curve S2 shown in FIG14.

[0225] Afterwards, the inflection points E1 (d1, i1) and E2 (d2, i2) corresponding to the current of curve S3 can be found. d1 and d2 are the distances from the center point, and the corresponding points in the one-dimensional bearing coordinate system are F1 (x1, 0) and F2 (x2, 0), where the third axial distance d1 = x0-x1, and the third axial distance d2 = x2-x0.

[0226] Similarly, the magnetic levitation rotor is rotated to directions Z2 to Z8 respectively to obtain the corresponding inflection points and distances. The corresponding one-dimensional bearing coordinate systems are F3(x3, 0), F4(x4, 0), F5(x5, 0), F6(x6, 0), F7(x7, 0), F8(x8, 0), F9(x9, 0), F10(x10, 0), F11(x11, 0), F12(x12, 0), F13(x13, 0), F14(x14, 0), F15(x15, 0) and F16(x16, 0).

[0227] From the above coordinate points, select the points closest to x0 on the left and right sides of x0 as the axial true protection gap boundary, and then determine the third protection bearing boundary, as shown in Figure 30.

[0228] Conversely, in other embodiments of the present disclosure, the voltage values ​​generated by sub-sensors 9 and 10 and the coil currents of the radial bearings can also be set to have opposite corresponding relationships, thereby obtaining a curve S1' that is completely opposite to that of Figure 9, as shown in Figure 11. Based on this, a third axial mapping relationship between the third axial distance and the coil current of the front radial bearing 131 can also be established to determine the third protective bearing boundary.

[0229] The present disclosure also provides a control method for controlling a magnetically suspended rotor of a magnetically suspended centrifugal compressor. The magnetically suspended centrifugal compressor includes the determination device 10 described in the above embodiment. The control method includes: controlling the suspension center of the magnetically suspended rotor to adjust within a protection boundary.

[0230] It can be understood that the process of determining the protection boundary range described in the control method of the present disclosure is as described above and will not be repeated here.

[0231] Correspondingly, referring to FIG. 31 , the present disclosure further provides a control device 20 for controlling a magnetically suspended rotor of a magnetically suspended centrifugal compressor. The magnetically suspended centrifugal compressor includes the determination device 10 described in the above embodiment. The control device 20 is configured to control the magnetically suspended rotor to adjust its suspension center within a protection boundary.

[0232] 32 , the present disclosure further provides a magnetic levitation centrifugal compressor 100. The magnetic levitation centrifugal compressor 100 includes the determination device 10 described in the above embodiment and the control device 20 described in the above embodiment.

[0233] The present disclosure further provides an air conditioning unit, which includes the magnetic levitation centrifugal compressor 100 according to the above embodiment.

[0234] The present disclosure also provides a non-volatile computer-readable storage medium containing a computer program. When the computer program is executed by one or more processors, the computer program implements any of the determination methods or control methods described in the above embodiments. For example, when the computer program is executed by a processor, the computer program implements the following steps of the determination method:

[0235] 01: Obtain the mapping relationship between the distance between the suspension center and the distance sensor and the coil current of the radial bearing;

[0236] 02: Determine multiple boundary distances in multiple directions when the magnetic levitation rotor is in contact with the inner wall of the protective bearing based on the mapping relationship and / or determine the axial boundary distance of the suspension center in the axial direction of the magnetic levitation rotor based on the mapping relationship, so as to determine the protective bearing boundary points in multiple directions inside the protective bearing and / or the axial protection boundary points of the rotor;

[0237] 03: A protection boundary is formed based on the protection bearing boundary points and / or the axial protection boundary points.

[0238] The computer-readable storage medium disclosed in the present invention applies the above-mentioned determination method or control method to accurately determine the corresponding protection boundary when the magnetic levitation rotor is in contact with the inner wall of the protective bearing, thereby determining the actual activity space of the magnetic levitation rotor after removing the clearance of the protective bearing, thereby ensuring the normal operation of the compressor.

[0239] The above embodiments merely illustrate several implementations of the present disclosure, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the scope of the present disclosure, all of which fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

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